Otherwise guest entry code might see incorrect L1 state (e.g paging state).

Fixes: 37be407b ("KVM: nSVM: Fix L1 state corruption upon return from SMM")
Signed-off-by: NMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210913140954.165665-3-mlevitsk@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Windows Server 2022 with Hyper-V role enabled failed to boot on KVM when
enlightened VMCS is advertised. Debugging revealed there are two exposed
secondary controls it is not happy with: SECONDARY_EXEC_ENABLE_VMFUNC and
SECONDARY_EXEC_SHADOW_VMCS. These controls are known to be unsupported,
as there are no corresponding fields in eVMCSv1 (see the comment above
EVMCS1_UNSUPPORTED_2NDEXEC definition).

Previously, commit 31de3d25 ("x86/kvm/hyper-v: move VMX controls
sanitization out of nested_enable_evmcs()") introduced the required
filtering mechanism for VMX MSRs but for some reason put only known
to be problematic (and not full EVMCS1_UNSUPPORTED_* lists) controls
there.

Note, Windows Server 2022 seems to have gained some sanity check for VMX
MSRs: it doesn't even try to launch a guest when there's something it
doesn't like, nested_evmcs_check_controls() mechanism can't catch the
problem.

Let's be bold this time and instead of playing whack-a-mole just filter out
all unsupported controls from VMX MSRs.

Fixes: 31de3d25 ("x86/kvm/hyper-v: move VMX controls sanitization out of nested_enable_evmcs()")
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210907163530.110066-1-vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

KASAN reports the following issue:

 BUG: KASAN: stack-out-of-bounds in kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
 Read of size 8 at addr ffffc9001364f638 by task qemu-kvm/4798

 CPU: 0 PID: 4798 Comm: qemu-kvm Tainted: G               X --------- ---
 Hardware name: AMD Corporation DAYTONA_X/DAYTONA_X, BIOS RYM0081C 07/13/2020
 Call Trace:
  dump_stack+0xa5/0xe6
  print_address_description.constprop.0+0x18/0x130
  ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
  __kasan_report.cold+0x7f/0x114
  ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
  kasan_report+0x38/0x50
  kasan_check_range+0xf5/0x1d0
  kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
  kvm_make_scan_ioapic_request_mask+0x84/0xc0 [kvm]
  ? kvm_arch_exit+0x110/0x110 [kvm]
  ? sched_clock+0x5/0x10
  ioapic_write_indirect+0x59f/0x9e0 [kvm]
  ? static_obj+0xc0/0xc0
  ? __lock_acquired+0x1d2/0x8c0
  ? kvm_ioapic_eoi_inject_work+0x120/0x120 [kvm]

The problem appears to be that 'vcpu_bitmap' is allocated as a single long
on stack and it should really be KVM_MAX_VCPUS long. We also seem to clear
the lower 16 bits of it with bitmap_zero() for no particular reason (my
guess would be that 'bitmap' and 'vcpu_bitmap' variables in
kvm_bitmap_or_dest_vcpus() caused the confusion: while the later is indeed
16-bit long, the later should accommodate all possible vCPUs).

Fixes: 7ee30bc1 ("KVM: x86: deliver KVM IOAPIC scan request to target vCPUs")
Fixes: 9a2ae9f6 ("KVM: x86: Zero the IOAPIC scan request dest vCPUs bitmap")
Reported-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: NMaxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210827092516.1027264-7-vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

A mirrored SEV-ES VM will need to call KVM_SEV_LAUNCH_UPDATE_VMSA to
setup its vCPUs and have them measured, and their VMSAs encrypted. Without
this change, it is impossible to have mirror VMs as part of SEV-ES VMs.

Also allow the guest status check and debugging commands since they do
not change any guest state.
Signed-off-by: NPeter Gonda <pgonda@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: Nathan Tempelman <natet@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Steve Rutherford <srutherford@google.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: 54526d1f ("KVM: x86: Support KVM VMs sharing SEV context", 2021-04-21)
Message-Id: <20210921150345.2221634-3-pgonda@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

For mirroring SEV-ES the mirror VM will need more then just the ASID.
The FD and the handle are required to all the mirror to call psp
commands. The mirror VM will need to call KVM_SEV_LAUNCH_UPDATE_VMSA to
setup its vCPUs' VMSAs for SEV-ES.
Signed-off-by: NPeter Gonda <pgonda@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: Nathan Tempelman <natet@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Steve Rutherford <srutherford@google.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: 54526d1f ("KVM: x86: Support KVM VMs sharing SEV context", 2021-04-21)
Message-Id: <20210921150345.2221634-2-pgonda@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Nested bus lock VM exits are not supported yet. If L2 triggers bus lock
VM exit, it will be directed to L1 VMM, which would cause unexpected
behavior. Therefore, handle L2's bus lock VM exits in L0 directly.

Fixes: fe6b6bc8 ("KVM: VMX: Enable bus lock VM exit")
Signed-off-by: NChenyi Qiang <chenyi.qiang@intel.com>
Reviewed-by: NSean Christopherson <seanjc@google.com>
Reviewed-by: NXiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20210914095041.29764-1-chenyi.qiang@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Use vcpu_idx to identify vCPU0 when updating HyperV's TSC page, which is
shared by all vCPUs and "owned" by vCPU0 (because vCPU0 is the only vCPU
that's guaranteed to exist).  Using kvm_get_vcpu() to find vCPU works,
but it's a rather odd and suboptimal method to check the index of a given
vCPU.

No functional change intended.
Signed-off-by: NSean Christopherson <seanjc@google.com>
Reviewed-by: NJim Mattson <jmattson@google.com>
Reviewed-by: NMaxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210910183220.2397812-3-seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Read vcpu->vcpu_idx directly instead of bouncing through the one-line
wrapper, kvm_vcpu_get_idx(), and drop the wrapper.  The wrapper is a
remnant of the original implementation and serves no purpose; remove it
before it gains more users.

Back when kvm_vcpu_get_idx() was added by commit 497d72d8 ("KVM: Add
kvm_vcpu_get_idx to get vcpu index in kvm->vcpus"), the implementation
was more than just a simple wrapper as vcpu->vcpu_idx did not exist and
retrieving the index meant walking over the vCPU array to find the given
vCPU.

When vcpu_idx was introduced by commit 8750e72a ("KVM: remember
position in kvm->vcpus array"), the helper was left behind, likely to
avoid extra thrash (but even then there were only two users, the original
arm usage having been removed at some point in the past).

No functional change intended.
Suggested-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NSean Christopherson <seanjc@google.com>
Reviewed-by: NMaxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210910183220.2397812-2-seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

According to Intel's SDM Vol2 and AMD's APM Vol3, when
CR4.TSD is set, use rdtsc/rdtscp instruction above privilege
level 0 should trigger a #GP.

Fixes: d7eb8203 ("KVM: SVM: Add intercept checks for remaining group7 instructions")
Signed-off-by: NHou Wenlong <houwenlong93@linux.alibaba.com>
Message-Id: <1297c0dd3f1bb47a6d089f850b629c7aa0247040.1629257115.git.houwenlong93@linux.alibaba.com>
Reviewed-by: NSean Christopherson <seanjc@google.com>
Reviewed-by: NJim Mattson <jmattson@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Require the target guest page to be writable when pinning memory for
RECEIVE_UPDATE_DATA.  Per the SEV API, the PSP writes to guest memory:

  The result is then encrypted with GCTX.VEK and written to the memory
  pointed to by GUEST_PADDR field.

Fixes: 15fb7de1 ("KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command")
Cc: stable@vger.kernel.org
Cc: Peter Gonda <pgonda@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210914210951.2994260-2-seanjc@google.com>
Reviewed-by: NBrijesh Singh <brijesh.singh@amd.com>
Reviewed-by: NPeter Gonda <pgonda@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

DECOMMISSION the current SEV context if binding an ASID fails after
RECEIVE_START.  Per AMD's SEV API, RECEIVE_START generates a new guest
context and thus needs to be paired with DECOMMISSION:

     The RECEIVE_START command is the only command other than the LAUNCH_START
     command that generates a new guest context and guest handle.

The missing DECOMMISSION can result in subsequent SEV launch failures,
as the firmware leaks memory and might not able to allocate more SEV
guest contexts in the future.

Note, LAUNCH_START suffered the same bug, but was previously fixed by
commit 934002cd ("KVM: SVM: Call SEV Guest Decommission if ASID
binding fails").

Cc: Alper Gun <alpergun@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: David Rienjes <rientjes@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: John Allen <john.allen@amd.com>
Cc: Peter Gonda <pgonda@google.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Vipin Sharma <vipinsh@google.com>
Cc: stable@vger.kernel.org
Reviewed-by: NMarc Orr <marcorr@google.com>
Acked-by: NBrijesh Singh <brijesh.singh@amd.com>
Fixes: af43cbbf ("KVM: SVM: Add support for KVM_SEV_RECEIVE_START command")
Signed-off-by: NMingwei Zhang <mizhang@google.com>
Reviewed-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210912181815.3899316-1-mizhang@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The update-VMSA ioctl touches data stored in struct kvm_vcpu, and
therefore should not be performed concurrently with any VCPU ioctl
that might cause KVM or the processor to use the same data.

Adds vcpu mutex guard to the VMSA updating code. Refactors out
__sev_launch_update_vmsa() function to deal with per vCPU parts
of sev_launch_update_vmsa().

Fixes: ad73109a ("KVM: SVM: Provide support to launch and run an SEV-ES guest")
Signed-off-by: NPeter Gonda <pgonda@google.com>
Cc: Marc Orr <marcorr@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: kvm@vger.kernel.org
Cc: stable@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Message-Id: <20210915171755.3773766-1-pgonda@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

"VMXON pointer" is saved in vmx->nested.vmxon_ptr since
commit 3573e22c ("KVM: nVMX: additional checks on
vmxon region"). Also, handle_vmptrld() & handle_vmclear()
now have logic to check the VMCS pointer against the VMXON
pointer.

So just remove the obsolete comments of handle_vmon().
Signed-off-by: NYu Zhang <yu.c.zhang@linux.intel.com>
Message-Id: <20210908171731.18885-1-yu.c.zhang@linux.intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Check the return of init_srcu_struct(), which can fail due to OOM, when
initializing the page track mechanism.  Lack of checking leads to a NULL
pointer deref found by a modified syzkaller.
Reported-by: NTCS Robot <tcs_robot@tencent.com>
Signed-off-by: NHaimin Zhang <tcs_kernel@tencent.com>
Message-Id: <1630636626-12262-1-git-send-email-tcs_kernel@tencent.com>
[Move the call towards the beginning of kvm_arch_init_vm. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Remove vcpu_vmx.nr_active_uret_msrs and its associated comment, which are
both defunct now that KVM keeps the list constant and instead explicitly
tracks which entries need to be loaded into hardware.

No functional change intended.

Fixes: ee9d22e0 ("KVM: VMX: Use flag to indicate "active" uret MSRs instead of sorting list")
Signed-off-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210908002401.1947049-1-seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Explicitly zero the guest's CR3 and mark it available+dirty at RESET/INIT.
Per Intel's SDM and AMD's APM, CR3 is zeroed at both RESET and INIT.  For
RESET, this is a nop as vcpu is zero-allocated.  For INIT, the bug has
likely escaped notice because no firmware/kernel puts its page tables root
at PA=0, let alone relies on INIT to get the desired CR3 for such page
tables.

Cc: stable@vger.kernel.org
Signed-off-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210921000303.400537-3-seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Mark all registers as available and dirty at vCPU creation, as the vCPU has
obviously not been loaded into hardware, let alone been given the chance to
be modified in hardware.  On SVM, reading from "uninitialized" hardware is
a non-issue as VMCBs are zero allocated (thus not truly uninitialized) and
hardware does not allow for arbitrary field encoding schemes.

On VMX, backing memory for VMCSes is also zero allocated, but true
initialization of the VMCS _technically_ requires VMWRITEs, as the VMX
architectural specification technically allows CPU implementations to
encode fields with arbitrary schemes.  E.g. a CPU could theoretically store
the inverted value of every field, which would result in VMREAD to a
zero-allocated field returns all ones.

In practice, only the AR_BYTES fields are known to be manipulated by
hardware during VMREAD/VMREAD; no known hardware or VMM (for nested VMX)
does fancy encoding of cacheable field values (CR0, CR3, CR4, etc...).  In
other words, this is technically a bug fix, but practically speakings it's
a glorified nop.

Failure to mark registers as available has been a lurking bug for quite
some time.  The original register caching supported only GPRs (+RIP, which
is kinda sorta a GPR), with the masks initialized at ->vcpu_reset().  That
worked because the two cacheable registers, RIP and RSP, are generally
speaking not read as side effects in other flows.

Arguably, commit aff48baa ("KVM: Fetch guest cr3 from hardware on
demand") was the first instance of failure to mark regs available.  While
_just_ marking CR3 available during vCPU creation wouldn't have fixed the
VMREAD from an uninitialized VMCS bug because ept_update_paging_mode_cr0()
unconditionally read vmcs.GUEST_CR3, marking CR3 _and_ intentionally not
reading GUEST_CR3 when it's available would have avoided VMREAD to a
technically-uninitialized VMCS.

Fixes: aff48baa ("KVM: Fetch guest cr3 from hardware on demand")
Fixes: 6de4f3ad ("KVM: Cache pdptrs")
Fixes: 6de12732 ("KVM: VMX: Optimize vmx_get_rflags()")
Fixes: 2fb92db1 ("KVM: VMX: Cache vmcs segment fields")
Fixes: bd31fe49 ("KVM: VMX: Add proper cache tracking for CR0")
Fixes: f98c1e77 ("KVM: VMX: Add proper cache tracking for CR4")
Fixes: 5addc235 ("KVM: VMX: Cache vmcs.EXIT_QUALIFICATION using arch avail_reg flags")
Fixes: 87915858 ("KVM: VMX: Cache vmcs.EXIT_INTR_INFO using arch avail_reg flags")
Signed-off-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210921000303.400537-2-seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

clang does not support -falign-jumps and only recently gained support
for -falign-loops. When one of the configuration options that adds these
flags is enabled, clang warns and all cc-{disable-warning,option} that
follow fail because -Werror gets added to test for the presence of this
warning:

clang-14: warning: optimization flag '-falign-jumps=0' is not supported
[-Wignored-optimization-argument]

To resolve this, add a couple of cc-option calls when building with
clang; gcc has supported these options since 3.2 so there is no point in
testing for their support. -falign-functions was implemented in clang-7,
-falign-loops was implemented in clang-14, and -falign-jumps has not
been implemented yet.

Link: https://lore.kernel.org/r/YSQE2f5teuvKLkON@Ryzen-9-3900X.localdomain/
Link: https://lore.kernel.org/r/20210824022640.2170859-2-nathan@kernel.org/Reported-by: Nkernel test robot <lkp@intel.com>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>
Acked-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NNathan Chancellor <nathan@kernel.org>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

Commit 0881ace2 ("mm/mremap: use pmd/pud_poplulate to update page
table entries") introduced a regression when running as Xen PV guest.

Today pmd_populate() for Xen PV assumes that the PFN inserted is
referencing a not yet used page table. In case of move_normal_pmd()
this is not true, resulting in WARN splats like:

[34321.304270] ------------[ cut here ]------------
[34321.304277] WARNING: CPU: 0 PID: 23628 at arch/x86/xen/multicalls.c:102 xen_mc_flush+0x176/0x1a0
[34321.304288] Modules linked in:
[34321.304291] CPU: 0 PID: 23628 Comm: apt-get Not tainted 5.14.1-20210906-doflr-mac80211debug+ #1
[34321.304294] Hardware name: MSI MS-7640/890FXA-GD70 (MS-7640)  , BIOS V1.8B1 09/13/2010
[34321.304296] RIP: e030:xen_mc_flush+0x176/0x1a0
[34321.304300] Code: 89 45 18 48 c1 e9 3f 48 89 ce e9 20 ff ff ff e8 60 03 00 00 66 90 5b 5d 41 5c 41 5d c3 48 c7 45 18 ea ff ff ff be 01 00 00 00 <0f> 0b 8b 55 00 48 c7 c7 10 97 aa 82 31 db 49 c7 c5 38 97 aa 82 65
[34321.304303] RSP: e02b:ffffc90000a97c90 EFLAGS: 00010002
[34321.304305] RAX: ffff88807d416398 RBX: ffff88807d416350 RCX: ffff88807d416398
[34321.304306] RDX: 0000000000000001 RSI: 0000000000000001 RDI: deadbeefdeadf00d
[34321.304308] RBP: ffff88807d416300 R08: aaaaaaaaaaaaaaaa R09: ffff888006160cc0
[34321.304309] R10: deadbeefdeadf00d R11: ffffea000026a600 R12: 0000000000000000
[34321.304310] R13: ffff888012f6b000 R14: 0000000012f6b000 R15: 0000000000000001
[34321.304320] FS:  00007f5071177800(0000) GS:ffff88807d400000(0000) knlGS:0000000000000000
[34321.304322] CS:  10000e030 DS: 0000 ES: 0000 CR0: 0000000080050033
[34321.304323] CR2: 00007f506f542000 CR3: 00000000160cc000 CR4: 0000000000000660
[34321.304326] Call Trace:
[34321.304331]  xen_alloc_pte+0x294/0x320
[34321.304334]  move_pgt_entry+0x165/0x4b0
[34321.304339]  move_page_tables+0x6fa/0x8d0
[34321.304342]  move_vma.isra.44+0x138/0x500
[34321.304345]  __x64_sys_mremap+0x296/0x410
[34321.304348]  do_syscall_64+0x3a/0x80
[34321.304352]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[34321.304355] RIP: 0033:0x7f507196301a
[34321.304358] Code: 73 01 c3 48 8b 0d 76 0e 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 19 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 46 0e 0c 00 f7 d8 64 89 01 48
[34321.304360] RSP: 002b:00007ffda1eecd38 EFLAGS: 00000246 ORIG_RAX: 0000000000000019
[34321.304362] RAX: ffffffffffffffda RBX: 000056205f950f30 RCX: 00007f507196301a
[34321.304363] RDX: 0000000001a00000 RSI: 0000000001900000 RDI: 00007f506dc56000
[34321.304364] RBP: 0000000001a00000 R08: 0000000000000010 R09: 0000000000000004
[34321.304365] R10: 0000000000000001 R11: 0000000000000246 R12: 00007f506dc56060
[34321.304367] R13: 00007f506dc56000 R14: 00007f506dc56060 R15: 000056205f950f30
[34321.304368] ---[ end trace a19885b78fe8f33e ]---
[34321.304370] 1 of 2 multicall(s) failed: cpu 0
[34321.304371]   call  2: op=12297829382473034410 arg=[aaaaaaaaaaaaaaaa] result=-22

Fix that by modifying xen_alloc_ptpage() to only pin the page table in
case it wasn't pinned already.

Fixes: 0881ace2 ("mm/mremap: use pmd/pud_poplulate to update page table entries")
Cc: <stable@vger.kernel.org>
Reported-by: NSander Eikelenboom <linux@eikelenboom.it>
Tested-by: NSander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20210908073640.11299-1-jgross@suse.comSigned-off-by: NJuergen Gross <jgross@suse.com>

A Xen PV guest doesn't have a legacy RTC device, so reset the legacy
RTC flag. Otherwise the following WARN splat will occur at boot:

[    1.333404] WARNING: CPU: 1 PID: 1 at /home/gross/linux/head/drivers/rtc/rtc-mc146818-lib.c:25 mc146818_get_time+0x1be/0x210
[    1.333404] Modules linked in:
[    1.333404] CPU: 1 PID: 1 Comm: swapper/0 Tainted: G        W         5.14.0-rc7-default+ #282
[    1.333404] RIP: e030:mc146818_get_time+0x1be/0x210
[    1.333404] Code: c0 64 01 c5 83 fd 45 89 6b 14 7f 06 83 c5 64 89 6b 14 41 83 ec 01 b8 02 00 00 00 44 89 63 10 5b 5d 41 5c 41 5d 41 5e 41 5f c3 <0f> 0b 48 c7 c7 30 0e ef 82 4c 89 e6 e8 71 2a 24 00 48 c7 c0 ff ff
[    1.333404] RSP: e02b:ffffc90040093df8 EFLAGS: 00010002
[    1.333404] RAX: 00000000000000ff RBX: ffffc90040093e34 RCX: 0000000000000000
[    1.333404] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 000000000000000d
[    1.333404] RBP: ffffffff82ef0e30 R08: ffff888005013e60 R09: 0000000000000000
[    1.333404] R10: ffffffff82373e9b R11: 0000000000033080 R12: 0000000000000200
[    1.333404] R13: 0000000000000000 R14: 0000000000000002 R15: ffffffff82cdc6d4
[    1.333404] FS:  0000000000000000(0000) GS:ffff88807d440000(0000) knlGS:0000000000000000
[    1.333404] CS:  10000e030 DS: 0000 ES: 0000 CR0: 0000000080050033
[    1.333404] CR2: 0000000000000000 CR3: 000000000260a000 CR4: 0000000000050660
[    1.333404] Call Trace:
[    1.333404]  ? wakeup_sources_sysfs_init+0x30/0x30
[    1.333404]  ? rdinit_setup+0x2b/0x2b
[    1.333404]  early_resume_init+0x23/0xa4
[    1.333404]  ? cn_proc_init+0x36/0x36
[    1.333404]  do_one_initcall+0x3e/0x200
[    1.333404]  kernel_init_freeable+0x232/0x28e
[    1.333404]  ? rest_init+0xd0/0xd0
[    1.333404]  kernel_init+0x16/0x120
[    1.333404]  ret_from_fork+0x1f/0x30

Cc: <stable@vger.kernel.org>
Fixes: 8d152e7a ("x86/rtc: Replace paravirt rtc check with platform legacy quirk")
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210903084937.19392-3-jgross@suse.comSigned-off-by: NJuergen Gross <jgross@suse.com>

The boot-time allocation interface for memblock is a mess, with
'memblock_alloc()' returning a virtual pointer, but then you are
supposed to free it with 'memblock_free()' that takes a _physical_
address.

Not only is that all kinds of strange and illogical, but it actually
causes bugs, when people then use it like a normal allocation function,
and it fails spectacularly on a NULL pointer:

   https://lore.kernel.org/all/20210912140820.GD25450@xsang-OptiPlex-9020/

or just random memory corruption if the debug checks don't catch it:

   https://lore.kernel.org/all/61ab2d0c-3313-aaab-514c-e15b7aa054a0@suse.cz/

I really don't want to apply patches that treat the symptoms, when the
fundamental cause is this horribly confusing interface.

I started out looking at just automating a sane replacement sequence,
but because of this mix or virtual and physical addresses, and because
people have used the "__pa()" macro that can take either a regular
kernel pointer, or just the raw "unsigned long" address, it's all quite
messy.

So this just introduces a new saner interface for freeing a virtual
address that was allocated using 'memblock_alloc()', and that was kept
as a regular kernel pointer.  And then it converts a couple of users
that are obvious and easy to test, including the 'xbc_nodes' case in
lib/bootconfig.c that caused problems.
Reported-by: Nkernel test robot <oliver.sang@intel.com>
Fixes: 40caa127 ("init: bootconfig: Remove all bootconfig data when the init memory is removed")
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are two cases for machine check recovery:

1) The machine check was triggered by ring3 (application) code.
   This is the simpler case. The machine check handler simply queues
   work to be executed on return to user. That code unmaps the page
   from all users and arranges to send a SIGBUS to the task that
   triggered the poison.

2) The machine check was triggered in kernel code that is covered by
   an exception table entry. In this case the machine check handler
   still queues a work entry to unmap the page, etc. but this will
   not be called right away because the #MC handler returns to the
   fix up code address in the exception table entry.

Problems occur if the kernel triggers another machine check before the
return to user processes the first queued work item.

Specifically, the work is queued using the ->mce_kill_me callback
structure in the task struct for the current thread. Attempting to queue
a second work item using this same callback results in a loop in the
linked list of work functions to call. So when the kernel does return to
user, it enters an infinite loop processing the same entry for ever.

There are some legitimate scenarios where the kernel may take a second
machine check before returning to the user.

1) Some code (e.g. futex) first tries a get_user() with page faults
   disabled. If this fails, the code retries with page faults enabled
   expecting that this will resolve the page fault.

2) Copy from user code retries a copy in byte-at-time mode to check
   whether any additional bytes can be copied.

On the other side of the fence are some bad drivers that do not check
the return value from individual get_user() calls and may access
multiple user addresses without noticing that some/all calls have
failed.

Fix by adding a counter (current->mce_count) to keep track of repeated
machine checks before task_work() is called. First machine check saves
the address information and calls task_work_add(). Subsequent machine
checks before that task_work call back is executed check that the address
is in the same page as the first machine check (since the callback will
offline exactly one page).

Expected worst case is four machine checks before moving on (e.g. one
user access with page faults disabled, then a repeat to the same address
with page faults enabled ... repeat in copy tail bytes). Just in case
there is some code that loops forever enforce a limit of 10.

 [ bp: Massage commit message, drop noinstr, fix typo, extend panic
   messages. ]

Fixes: 5567d11c ("x86/mce: Send #MC singal from task work")
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/YT/IJ9ziLqmtqEPu@agluck-desk2.amr.corp.intel.com

Commit 865c50e1 ("x86/uaccess: utilize CONFIG_CC_HAS_ASM_GOTO_OUTPUT")
added an optimised version of __get_user_asm() for x86 using 'asm goto'.

Like the non-optimised code, the 32-bit implementation of 64-bit
get_user() expands to a pair of 32-bit accesses.  Unlike the
non-optimised code, the _original_ pointer is incremented to copy the
high word instead of loading through a new pointer explicitly
constructed to point at a 32-bit type.  Consequently, if the pointer
points at a 64-bit type then we end up loading the wrong data for the
upper 32-bits.

This was observed as a mount() failure in Android targeting i686 after
b0cfcdd9 ("d_path: make 'prepend()' fill up the buffer exactly on
overflow") because the call to copy_from_kernel_nofault() from
prepend_copy() ends up in __get_kernel_nofault() and casts the source
pointer to a 'u64 __user *'.  An attempt to mount at "/debug_ramdisk"
therefore ends up failing trying to mount "/debumdismdisk".

Use the existing '__gu_ptr' source pointer to unsigned int for 32-bit
__get_user_asm_u64() instead of the original pointer.

Cc: Bill Wendling <morbo@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Reported-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: 865c50e1 ("x86/uaccess: utilize CONFIG_CC_HAS_ASM_GOTO_OUTPUT")
Signed-off-by: NWill Deacon <will@kernel.org>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>
Tested-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It is not a good practice to allocate a cpumask on stack, given it may
consume up to 1 kilobytes of stack space if the kernel is configured to
have 8192 cpus.

The internal helper functions __send_ipi_mask{,_ex} need to loop over
the provided mask anyway, so it is not too difficult to skip `self'
there. We can thus do away with the on-stack cpumask in
hv_send_ipi_mask_allbutself.

Adjust call sites of __send_ipi_mask as needed.
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Suggested-by: NMichael Kelley <mikelley@microsoft.com>
Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Fixes: 68bb7bfb ("X86/Hyper-V: Enable IPI enlightenments")
Signed-off-by: NWei Liu <wei.liu@kernel.org>
Reviewed-by: NMichael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210910185714.299411-3-wei.liu@kernel.org

All users of compat_alloc_user_space() and copy_in_user() have been
removed from the kernel, only a few functions in sparc remain that can be
changed to calling arch_copy_in_user() instead.

Link: https://lkml.kernel.org/r/20210727144859.4150043-7-arnd@kernel.orgSigned-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

These are all handled correctly when calling the native system call entry
point, so remove the special cases.

Link: https://lkml.kernel.org/r/20210727144859.4150043-6-arnd@kernel.orgSigned-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Jiri Olsa reported a fault when running:

  # cat /proc/kallsyms | grep ksys_read
  ffffffff8136d580 T ksys_read
  # objdump -d --start-address=0xffffffff8136d580 --stop-address=0xffffffff8136d590 /proc/kcore

  /proc/kcore:     file format elf64-x86-64

  Segmentation fault

  general protection fault, probably for non-canonical address 0xf887ffcbff000: 0000 [#1] SMP PTI
  CPU: 12 PID: 1079 Comm: objdump Not tainted 5.14.0-rc5qemu+ #508
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-4.fc34 04/01/2014
  RIP: 0010:kern_addr_valid
  Call Trace:
   read_kcore
   ? rcu_read_lock_sched_held
   ? rcu_read_lock_sched_held
   ? rcu_read_lock_sched_held
   ? trace_hardirqs_on
   ? rcu_read_lock_sched_held
   ? lock_acquire
   ? lock_acquire
   ? rcu_read_lock_sched_held
   ? lock_acquire
   ? rcu_read_lock_sched_held
   ? rcu_read_lock_sched_held
   ? rcu_read_lock_sched_held
   ? lock_release
   ? _raw_spin_unlock
   ? __handle_mm_fault
   ? rcu_read_lock_sched_held
   ? lock_acquire
   ? rcu_read_lock_sched_held
   ? lock_release
   proc_reg_read
   ? vfs_read
   vfs_read
   ksys_read
   do_syscall_64
   entry_SYSCALL_64_after_hwframe

The fault happens because kern_addr_valid() dereferences existent but not
present PMD in the high kernel mappings.

Such PMDs are created when free_kernel_image_pages() frees regions larger
than 2Mb. In this case, a part of the freed memory is mapped with PMDs and
the set_memory_np_noalias() -> ... -> __change_page_attr() sequence will
mark the PMD as not present rather than wipe it completely.

Have kern_addr_valid() check whether higher level page table entries are
present before trying to dereference them to fix this issue and to avoid
similar issues in the future.

Stable backporting note:
------------------------

Note that the stable marking is for all active stable branches because
there could be cases where pagetable entries exist but are not valid -
see 9a14aefc ("x86: cpa, fix lookup_address"), for example. So make
sure to be on the safe side here and use pXY_present() accessors rather
than pXY_none() which could #GP when accessing pages in the direct map.

Also see:

  c40a56a7 ("x86/mm/init: Remove freed kernel image areas from alias mapping")

for more info.
Reported-by: NJiri Olsa <jolsa@redhat.com>
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Acked-by: NDave Hansen <dave.hansen@intel.com>
Tested-by: NJiri Olsa <jolsa@redhat.com>
Cc: <stable@vger.kernel.org>	# 4.4+
Link: https://lkml.kernel.org/r/20210819132717.19358-1-rppt@kernel.org

This CONFIG option was removed in commit 278b13ce ("Input: remove
input_polled_dev implementation") so there's no point to keep it in
defconfigs any longer.

Get rid of the leftover for all arches.

Link: https://lkml.kernel.org/r/20210726074741.1062-1-yuzenghui@huawei.comSigned-off-by: NZenghui Yu <yuzenghui@huawei.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The parameter is unused, let's remove it.

Link: https://lkml.kernel.org/r/20210712124052.26491-3-david@redhat.comSigned-off-by: NDavid Hildenbrand <david@redhat.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc]
Acked-by: Heiko Carstens <hca@linux.ibm.com>	[s390]
Reviewed-by: NPankaj Gupta <pankaj.gupta@ionos.com>
Reviewed-by: NOscar Salvador <osalvador@suse.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Sergei Trofimovich <slyfox@gentoo.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Michel Lespinasse <michel@lespinasse.org>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: Joe Perches <joe@perches.com>
Cc: Pierre Morel <pmorel@linux.ibm.com>
Cc: Jia He <justin.he@arm.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Scott Cheloha <cheloha@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When MSR_IA32_TSC_ADJUST is written by guest due to TSC ADJUST feature
especially there's a big tsc warp (like a new vCPU is hot-added into VM
which has been up for a long time), tsc_offset is added by a large value
then go back to guest. This causes system time jump as tsc_timestamp is
not adjusted in the meantime and pvclock monotonic character.
To fix this, just notify kvm to update vCPU's guest time before back to
guest.

Cc: stable@vger.kernel.org
Signed-off-by: NZelin Deng <zelin.deng@linux.alibaba.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Message-Id: <1619576521-81399-2-git-send-email-zelin.deng@linux.alibaba.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

It is reasonable for these functions to be used only in some configurations,
for example only if the host is 64-bits (and therefore supports 64-bit
guests).  It is also reasonable to keep the role_regs and role accessors
in sync even though some of the accessors may be used only for one of the
two sets (as is the case currently for CR4.LA57)..

Because clang reports warnings for unused inlines declared in a .c file,
mark both sets of accessors as __maybe_unused.
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Commit f4e61f0c ("x86/kvm: Fix broken irq restoration in kvm_wait")
replaced "local_irq_restore() when IRQ enabled" with "local_irq_enable()
when IRQ enabled" to suppress a warnning.

Although there is no similar debugging warnning for doing local_irq_enable()
when IRQ enabled as doing local_irq_restore() in the same IRQ situation.  But
doing local_irq_enable() when IRQ enabled is no less broken as doing
local_irq_restore() and we'd better avoid it.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NLai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20210814035129.154242-1-jiangshanlai@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Move "lpage_disallowed_link" out of the first 64 bytes, i.e. out of the
first cache line, of kvm_mmu_page so that "spt" and to a lesser extent
"gfns" land in the first cache line.  "lpage_disallowed_link" is accessed
relatively infrequently compared to "spt", which is accessed any time KVM
is walking and/or manipulating the shadow page tables.

No functional change intended.
Signed-off-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210901221023.1303578-4-seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Move "tdp_mmu_page" into the 1-byte void left by the recently removed
"mmio_cached" so that it resides in the first 64 bytes of kvm_mmu_page,
i.e. in the same cache line as the most commonly accessed fields.

Don't bother wrapping tdp_mmu_page in CONFIG_X86_64, including the field in
32-bit builds doesn't affect the size of kvm_mmu_page, and a future patch
can always wrap the field in the unlikely event KVM gains a 1-byte flag
that is 32-bit specific.

Note, the size of kvm_mmu_page is also unchanged on CONFIG_X86_64=y due
to it previously sharing an 8-byte chunk with write_flooding_count.

No functional change intended.
Signed-off-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210901221023.1303578-3-seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Revert a misguided illegal GPA check when "translating" a non-nested GPA.
The check is woefully incomplete as it does not fill in @exception as
expected by all callers, which leads to KVM attempting to inject a bogus
exception, potentially exposing kernel stack information in the process.

 WARNING: CPU: 0 PID: 8469 at arch/x86/kvm/x86.c:525 exception_type+0x98/0xb0 arch/x86/kvm/x86.c:525
 CPU: 1 PID: 8469 Comm: syz-executor531 Not tainted 5.14.0-rc7-syzkaller #0
 RIP: 0010:exception_type+0x98/0xb0 arch/x86/kvm/x86.c:525
 Call Trace:
  x86_emulate_instruction+0xef6/0x1460 arch/x86/kvm/x86.c:7853
  kvm_mmu_page_fault+0x2f0/0x1810 arch/x86/kvm/mmu/mmu.c:5199
  handle_ept_misconfig+0xdf/0x3e0 arch/x86/kvm/vmx/vmx.c:5336
  __vmx_handle_exit arch/x86/kvm/vmx/vmx.c:6021 [inline]
  vmx_handle_exit+0x336/0x1800 arch/x86/kvm/vmx/vmx.c:6038
  vcpu_enter_guest+0x2a1c/0x4430 arch/x86/kvm/x86.c:9712
  vcpu_run arch/x86/kvm/x86.c:9779 [inline]
  kvm_arch_vcpu_ioctl_run+0x47d/0x1b20 arch/x86/kvm/x86.c:10010
  kvm_vcpu_ioctl+0x49e/0xe50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3652

The bug has escaped notice because practically speaking the GPA check is
useless.  The GPA check in question only comes into play when KVM is
walking guest page tables (or "translating" CR3), and KVM already handles
illegal GPA checks by setting reserved bits in rsvd_bits_mask for each
PxE, or in the case of CR3 for loading PTDPTRs, manually checks for an
illegal CR3.  This particular failure doesn't hit the existing reserved
bits checks because syzbot sets guest.MAXPHYADDR=1, and IA32 architecture
simply doesn't allow for such an absurd MAXPHYADDR, e.g. 32-bit paging
doesn't define any reserved PA bits checks, which KVM emulates by only
incorporating the reserved PA bits into the "high" bits, i.e. bits 63:32.

Simply remove the bogus check.  There is zero meaningful value and no
architectural justification for supporting guest.MAXPHYADDR < 32, and
properly filling the exception would introduce non-trivial complexity.

This reverts commit ec7771ab.

Fixes: ec7771ab ("KVM: x86: mmu: Add guest physical address check in translate_gpa()")
Cc: stable@vger.kernel.org
Reported-by: syzbot+200c08e88ae818f849ce@syzkaller.appspotmail.com
Signed-off-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210831164224.1119728-2-seanjc@google.com>
Reviewed-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

After reverting and restoring the fast tlb invalidation patch series,
the mmio_cached is not removed. Hence a unused field is left in
kvm_mmu_page.

Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: NJia He <justin.he@arm.com>
Message-Id: <20210830145336.27183-1-justin.he@arm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Support for 710 VCPUs was tested by Red Hat since RHEL-8.4,
so increase KVM_SOFT_MAX_VCPUS to 710.
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210903211600.2002377-4-ehabkost@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Increase KVM_MAX_VCPUS to 1024, so we can test larger VMs.

I'm not changing KVM_SOFT_MAX_VCPUS yet because I'm afraid it
might involve complicated questions around the meaning of
"supported" and "recommended" in the upstream tree.
KVM_SOFT_MAX_VCPUS will be changed in a separate patch.

For reference, visible effects of this change are:
- KVM_CAP_MAX_VCPUS will now return 1024 (of course)
- Default value for CPUID[HYPERV_CPUID_IMPLEMENT_LIMITS (00x40000005)].EAX
  will now be 1024
- KVM_MAX_VCPU_ID will change from 1151 to 4096
- Size of struct kvm will increase from 19328 to 22272 bytes
  (in x86_64)
- Size of struct kvm_ioapic will increase from 1780 to 5084 bytes
  (in x86_64)
- Bitmap stack variables that will grow:
  - At kvm_hv_flush_tlb() kvm_hv_send_ipi(),
    vp_bitmap[] and vcpu_bitmap[] will now be 128 bytes long
  - vcpu_bitmap at bioapic_write_indirect() will be 128 bytes long
    once patch "KVM: x86: Fix stack-out-of-bounds memory access
    from ioapic_write_indirect()" is applied
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210903211600.2002377-3-ehabkost@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Instead of requiring KVM_MAX_VCPU_ID to be manually increased
every time we increase KVM_MAX_VCPUS, set it to 4*KVM_MAX_VCPUS.
This should be enough for CPU topologies where Cores-per-Package
and Packages-per-Socket are not powers of 2.

In practice, this increases KVM_MAX_VCPU_ID from 1023 to 1152.
The only side effect of this change is making some fields in
struct kvm_ioapic larger, increasing the struct size from 1628 to
1780 bytes (in x86_64).
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210903211600.2002377-2-ehabkost@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

If we are emulating an invalid guest state, we don't have a correct
exit reason, and thus we shouldn't do anything in this function.
Signed-off-by: NMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210826095750.1650467-2-mlevitsk@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 95b5a48c ("KVM: VMX: Handle NMIs, #MCs and async #PFs in common irqs-disabled fn", 2019-06-18)
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>