The User-Mode Instruction Prevention feature present in recent Intel
processor prevents a group of instructions (sgdt, sidt, sldt, smsw, and
str) from being executed with CPL > 0. Otherwise, a general protection
fault is issued.

UMIP instructions in general are also able to trigger vmexits, so we can
actually emulate UMIP on older processors.  This commit sets up the
infrastructure so that kvm-intel.ko and kvm-amd.ko can set the UMIP
feature bit for CPUID even if the feature is not actually available
in hardware.
Reviewed-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Add the CPUID bits, make the CR4.UMIP bit not reserved anymore, and
add UMIP support for instructions that are already emulated by KVM.
Reviewed-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Implementation of the unpinned APIC page didn't update the VMCS address
cache when invalidation was done through range mmu notifiers.
This became a problem when the page notifier was removed.

Re-introduce the arch-specific helper and call it from ...range_start.
Reported-by: NFabian Grünbichler <f.gruenbichler@proxmox.com>
Fixes: 38b99173 ("kvm: vmx: Implement set_apic_access_page_addr")
Fixes: 369ea824 ("mm/rmap: update to new mmu_notifier semantic v2")
Cc: <stable@vger.kernel.org>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NAndrea Arcangeli <aarcange@redhat.com>
Tested-by: NWanpeng Li <wanpeng.li@hotmail.com>
Tested-by: NFabian Grünbichler <f.gruenbichler@proxmox.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Currently, every time a VCPU is scheduled out, the host kernel will
first save the guest FPU/xstate context, then load the qemu userspace
FPU context, only to then immediately save the qemu userspace FPU
context back to memory. When scheduling in a VCPU, the same extraneous
FPU loads and saves are done.

This could be avoided by moving from a model where the guest FPU is
loaded and stored with preemption disabled, to a model where the
qemu userspace FPU is swapped out for the guest FPU context for
the duration of the KVM_RUN ioctl.

This is done under the VCPU mutex, which is also taken when other
tasks inspect the VCPU FPU context, so the code should already be
safe for this change. That should come as no surprise, given that
s390 already has this optimization.

This can fix a bug where KVM calls get_user_pages while owning the
FPU, and the file system ends up requesting the FPU again:

    [258270.527947]  __warn+0xcb/0xf0
    [258270.527948]  warn_slowpath_null+0x1d/0x20
    [258270.527951]  kernel_fpu_disable+0x3f/0x50
    [258270.527953]  __kernel_fpu_begin+0x49/0x100
    [258270.527955]  kernel_fpu_begin+0xe/0x10
    [258270.527958]  crc32c_pcl_intel_update+0x84/0xb0
    [258270.527961]  crypto_shash_update+0x3f/0x110
    [258270.527968]  crc32c+0x63/0x8a [libcrc32c]
    [258270.527975]  dm_bm_checksum+0x1b/0x20 [dm_persistent_data]
    [258270.527978]  node_prepare_for_write+0x44/0x70 [dm_persistent_data]
    [258270.527985]  dm_block_manager_write_callback+0x41/0x50 [dm_persistent_data]
    [258270.527988]  submit_io+0x170/0x1b0 [dm_bufio]
    [258270.527992]  __write_dirty_buffer+0x89/0x90 [dm_bufio]
    [258270.527994]  __make_buffer_clean+0x4f/0x80 [dm_bufio]
    [258270.527996]  __try_evict_buffer+0x42/0x60 [dm_bufio]
    [258270.527998]  dm_bufio_shrink_scan+0xc0/0x130 [dm_bufio]
    [258270.528002]  shrink_slab.part.40+0x1f5/0x420
    [258270.528004]  shrink_node+0x22c/0x320
    [258270.528006]  do_try_to_free_pages+0xf5/0x330
    [258270.528008]  try_to_free_pages+0xe9/0x190
    [258270.528009]  __alloc_pages_slowpath+0x40f/0xba0
    [258270.528011]  __alloc_pages_nodemask+0x209/0x260
    [258270.528014]  alloc_pages_vma+0x1f1/0x250
    [258270.528017]  do_huge_pmd_anonymous_page+0x123/0x660
    [258270.528021]  handle_mm_fault+0xfd3/0x1330
    [258270.528025]  __get_user_pages+0x113/0x640
    [258270.528027]  get_user_pages+0x4f/0x60
    [258270.528063]  __gfn_to_pfn_memslot+0x120/0x3f0 [kvm]
    [258270.528108]  try_async_pf+0x66/0x230 [kvm]
    [258270.528135]  tdp_page_fault+0x130/0x280 [kvm]
    [258270.528149]  kvm_mmu_page_fault+0x60/0x120 [kvm]
    [258270.528158]  handle_ept_violation+0x91/0x170 [kvm_intel]
    [258270.528162]  vmx_handle_exit+0x1ca/0x1400 [kvm_intel]

No performance changes were detected in quick ping-pong tests on
my 4 socket system, which is expected since an FPU+xstate load is
on the order of 0.1us, while ping-ponging between CPUs is on the
order of 20us, and somewhat noisy.

Cc: stable@vger.kernel.org
Signed-off-by: NRik van Riel <riel@redhat.com>
Suggested-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
[Fixed a bug where reset_vcpu called put_fpu without preceding load_fpu,
 which happened inside from KVM_CREATE_VCPU ioctl. - Radim]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

In case of instruction-decode failure or emulation failure,
x86_emulate_instruction() will call reexecute_instruction() which will
attempt to use the cr2 value passed to x86_emulate_instruction().
However, when x86_emulate_instruction() is called from
emulate_instruction(), cr2 is not passed (passed as 0) and therefore
it doesn't make sense to execute reexecute_instruction() logic at all.

Fixes: 51d8b661 ("KVM: cleanup emulate_instruction")
Signed-off-by: NLiran Alon <liran.alon@oracle.com>
Reviewed-by: NNikita Leshenko <nikita.leshchenko@oracle.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Commit 05cade71 ("KVM: nSVM: fix SMI injection in guest mode") made
KVM mask SMI if GIF=0 but it didn't do anything to unmask it when GIF is
enabled.

The issue manifests for me as a significantly longer boot time of Windows
guests when running with SMM-enabled OVMF.

This commit fixes it by intercepting STGI instead of requesting immediate
exit if the reason why SMM was masked is GIF.

Fixes: 05cade71 ("KVM: nSVM: fix SMI injection in guest mode")
Signed-off-by: NLadi Prosek <lprosek@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Entering SMM while running in guest mode wasn't working very well because several
pieces of the vcpu state were left set up for nested operation.

Some of the issues observed:

* L1 was getting unexpected VM exits (using L1 interception controls but running
  in SMM execution environment)
* MMU was confused (walk_mmu was still set to nested_mmu)
* INTERCEPT_SMI was not emulated for L1 (KVM never injected SVM_EXIT_SMI)

Intel SDM actually prescribes the logical processor to "leave VMX operation" upon
entering SMM in 34.14.1 Default Treatment of SMI Delivery. AMD doesn't seem to
document this but they provide fields in the SMM state-save area to stash the
current state of SVM. What we need to do is basically get out of guest mode for
the duration of SMM. All this completely transparent to L1, i.e. L1 is not given
control and no L1 observable state changes.

To avoid code duplication this commit takes advantage of the existing nested
vmexit and run functionality, perhaps at the cost of efficiency. To get out of
guest mode, nested_svm_vmexit is called, unchanged. Re-entering is performed using
enter_svm_guest_mode.

This commit fixes running Windows Server 2016 with Hyper-V enabled in a VM with
OVMF firmware (OVMF_CODE-need-smm.fd).
Signed-off-by: NLadi Prosek <lprosek@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Similar to NMI, there may be ISA specific reasons why an SMI cannot be
injected into the guest. This commit adds a new smi_allowed callback to
be implemented in following commits.
Signed-off-by: NLadi Prosek <lprosek@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Entering and exiting SMM may require ISA specific handling under certain
circumstances. This commit adds two new callbacks with empty implementations.
Actual functionality will be added in following commits.

* pre_enter_smm() is to be called when injecting an SMM, before any
  SMM related vcpu state has been changed
* pre_leave_smm() is to be called when emulating the RSM instruction,
  when the vcpu is in real mode and before any SMM related vcpu state
  has been restored
Signed-off-by: NLadi Prosek <lprosek@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The 32bit and the 64bit implementation of default_cpu_present_to_apicid()
and default_check_phys_apicid_present() are exactly the same, but
implemented and located differently.

Move them to common apic code and get rid of the pointless difference.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Tested-by: NJuergen Gross <jgross@suse.com>
Tested-by: NYu Chen <yu.c.chen@intel.com>
Acked-by: NJuergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213153.757329991@linutronix.de

Modify struct kvm_x86_ops.arch.apicv_active() to take struct kvm_vcpu
pointer as parameter in preparation to subsequent changes.
Signed-off-by: NSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

The commit

	9dd21e104bc ('KVM: x86: simplify handling of PKRU')

removed all users and providers of that call-back, but
didn't remove it. Remove it now.
Signed-off-by: NJoerg Roedel <jroedel@suse.de>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Calls to mmu_notifier_invalidate_page() were replaced by calls to
mmu_notifier_invalidate_range() and are now bracketed by calls to
mmu_notifier_invalidate_range_start()/end()

Remove now useless invalidate_page callback.

Changed since v1 (Linus Torvalds)
    - remove now useless kvm_arch_mmu_notifier_invalidate_page()
Signed-off-by: NJérôme Glisse <jglisse@redhat.com>
Tested-by: NMike Galbraith <efault@gmx.de>
Tested-by: NAdam Borowski <kilobyte@angband.pl>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move it to struct kvm_arch_vcpu, replacing guest_pkru_valid with a
simple comparison against the host value of the register.  The write of
PKRU in addition can be skipped if the guest has not enabled the feature.
Once we do this, we need not test OSPKE in the host anymore, because
guest_CR4.PKE=1 implies host_CR4.PKE=1.

The static PKU test is kept to elide the code on older CPUs.
Suggested-by: NYang Zhang <zy107165@alibaba-inc.com>
Fixes: 1be0e61c
Cc: stable@vger.kernel.org
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

vmx_complete_interrupts() assumes that the exception is always injected,
so it can be dropped by kvm_clear_exception_queue().  However,
an exception cannot be injected immediately if it is: 1) originally
destined to a nested guest; 2) trapped to cause a vmexit; 3) happening
right after VMLAUNCH/VMRESUME, i.e. when nested_run_pending is true.

This patch applies to exceptions the same algorithm that is used for
NMIs, replacing exception.reinject with "exception.injected" (equivalent
to nmi_injected).

exception.pending now represents an exception that is queued and whose
side effects (e.g., update RFLAGS.RF or DR7) have not been applied yet.
If exception.pending is true, the exception might result in a nested
vmexit instead, too (in which case the side effects must not be applied).

exception.injected instead represents an exception that is going to be
injected into the guest at the next vmentry.
Reported-by: NRadim Krčmář <rkrcmar@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

This patch exposes 5 level page table feature to the VM.
At the same time, the canonical virtual address checking is
extended to support both 48-bits and 57-bits address width.
Signed-off-by: NYu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Extends the shadow paging code, so that 5 level shadow page
table can be constructed if VM is running in 5 level paging
mode.

Also extends the ept code, so that 5 level ept table can be
constructed if maxphysaddr of VM exceeds 48 bits. Unlike the
shadow logic, KVM should still use 4 level ept table for a VM
whose physical address width is less than 48 bits, even when
the VM is running in 5 level paging mode.
Signed-off-by: NYu Zhang <yu.c.zhang@linux.intel.com>
[Unconditionally reset the MMU context in kvm_cpuid_update.
 Changing MAXPHYADDR invalidates the reserved bit bitmasks.
 - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Now we have 4 level page table and 5 level page table in 64 bits
long mode, let's rename the PT64_ROOT_LEVEL to PT64_ROOT_4LEVEL,
then we can use PT64_ROOT_5LEVEL for 5 level page table, it's
helpful to make the code more clear.

Also PT64_ROOT_MAX_LEVEL is defined as 4, so that we can just
redefine it to 5 whenever a replacement is needed for 5 level
paging.
Signed-off-by: NYu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Currently, KVM uses CR3_L_MODE_RESERVED_BITS to check the
reserved bits in CR3. Yet the length of reserved bits in
guest CR3 should be based on the physical address width
exposed to the VM. This patch changes CR3 check logic to
calculate the reserved bits at runtime.
Signed-off-by: NYu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

When a guest causes a page fault which requires emulation, the
vcpu->arch.gpa_available flag is set to indicate that cr2 contains a
valid GPA.

Currently, emulator_read_write_onepage() makes use of gpa_available flag
to avoid a guest page walk for a known MMIO regions. Lets not limit
the gpa_available optimization to just MMIO region. The patch extends
the check to avoid page walk whenever gpa_available flag is set.
Signed-off-by: NBrijesh Singh <brijesh.singh@amd.com>
[Fix EPT=0 according to Wanpeng Li's fix, plus ensure VMX also uses the
 new code. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
[Moved "ret < 0" to the else brach, as per David's review. - Radim]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

This is the same as commit 14727754 ("kvm: svm: Add support for
additional SVM NPF error codes", 2016-11-23), but for Intel processors.
In this case, the exit qualification field's bit 8 says whether the
EPT violation occurred while translating the guest's final physical
address or rather while translating the guest page tables.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

get_cpl requires vcpu_load, so we must cache the result (whether the
vcpu was preempted when its cpl=0) in kvm_vcpu_arch.
Signed-off-by: NLongpeng(Mike) <longpeng2@huawei.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Update the KVM support to work with SME. The VMCB has a number of fields
where physical addresses are used and these addresses must contain the
memory encryption mask in order to properly access the encrypted memory.
Also, use the memory encryption mask when creating and using the nested
page tables.
Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NBorislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: kasan-dev@googlegroups.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/89146eccfa50334409801ff20acd52a90fb5efcf.1500319216.git.thomas.lendacky@amd.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Hyper-V identifies vCPUs by Virtual Processor Index, which can be
queried via HV_X64_MSR_VP_INDEX msr.  It is defined by the spec as a
sequential number which can't exceed the maximum number of vCPUs per VM.
APIC ids can be sparse and thus aren't a valid replacement for VP
indices.

Current KVM uses its internal vcpu index as VP_INDEX.  However, to make
it predictable and persistent across VM migrations, the userspace has to
control the value of VP_INDEX.

This patch achieves that, by storing vp_index explicitly on vcpu, and
allowing HV_X64_MSR_VP_INDEX to be set from the host side.  For
compatibility it's initialized to KVM vcpu index.  Also a few variables
are renamed to make clear distinction betweed this Hyper-V vp_index and
KVM vcpu_id (== APIC id).  Besides, a new capability,
KVM_CAP_HYPERV_VP_INDEX, is added to allow the userspace to skip
attempting msr writes where unsupported, to avoid spamming error logs.
Signed-off-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Adds another flag bit (bit 2) to MSR_KVM_ASYNC_PF_EN. If bit 2 is 1,
async page faults are delivered to L1 as #PF vmexits; if bit 2 is 0,
kvm_can_do_async_pf returns 0 if in guest mode.

This is similar to what svm.c wanted to do all along, but it is only
enabled for Linux as L1 hypervisor.  Foreign hypervisors must never
receive async page faults as vmexits, because they'd probably be very
confused about that.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Add an nested_apf field to vcpu->arch.exception to identify an async page
fault, and constructs the expected vm-exit information fields. Force a
nested VM exit from nested_vmx_check_exception() if the injected #PF is
async page fault.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

This patch adds the L1 guest async page fault #PF vmexit handler, such
by L1 similar to ordinary async page fault.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
[Passed insn parameters to kvm_mmu_page_fault().]
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

This patch removes all arguments except the first in
kvm_x86_ops->queue_exception since they can extract the arguments from
vcpu->arch.exception themselves.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

There is a flaw in the Hyper-V SynIC implementation in KVM: when message
page or event flags page is enabled by setting the corresponding msr,
KVM zeroes it out.  This is problematic because on migration the
corresponding MSRs are loaded on the destination, so the content of
those pages is lost.

This went unnoticed so far because the only user of those pages was
in-KVM hyperv synic timers, which could continue working despite that
zeroing.

Newer QEMU uses those pages for Hyper-V VMBus implementation, and
zeroing them breaks the migration.

Besides, in newer QEMU the content of those pages is fully managed by
QEMU, so zeroing them is undesirable even when writing the MSRs from the
guest side.

To support this new scheme, introduce a new capability,
KVM_CAP_HYPERV_SYNIC2, which, when enabled, makes sure that the synic
pages aren't zeroed out in KVM.
Signed-off-by: NRoman Kagan <rkagan@virtuozzo.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

The backwards_tsc_observed global introduced in commit 16a96021 is never
reset to false. If a VM happens to be running while the host is suspended
(a common source of the TSC jumping backwards), master clock will never
be enabled again for any VM. In contrast, if no VM is running while the
host is suspended, master clock is unaffected. This is inconsistent and
unnecessarily strict. Let's track the backwards_tsc_observed variable
separately and let each VM start with a clean slate.

Real world impact: My Windows VMs get slower after my laptop undergoes a
suspend/resume cycle. The only way to get the perf back is unloading and
reloading the kvm module.
Signed-off-by: NLadi Prosek <lprosek@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Adds the plumbing to disable A/D bits in the MMU based on a new role
bit, ad_disabled. When A/D is disabled, the MMU operates as though A/D
aren't available (i.e., using access tracking faults instead).

To avoid SP -> kvm_mmu_page.role.ad_disabled lookups all over the
place, A/D disablement is now stored in the SPTE. This state is stored
in the SPTE by tweaking the use of SPTE_SPECIAL_MASK for access
tracking. Rather than just setting SPTE_SPECIAL_MASK when an
access-tracking SPTE is non-present, we now always set
SPTE_SPECIAL_MASK for access-tracking SPTEs.
Signed-off-by: NPeter Feiner <pfeiner@google.com>
[Use role.ad_disabled even for direct (non-shadow) EPT page tables.  Add
 documentation and a few MMU_WARN_ONs. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Marc Zyngier suggested that we define the arch specific VCPU request
base, rather than requiring each arch to remember to start from 8.
That suggestion, along with Radim Krcmar's recent VCPU request flag
addition, snowballed into defining something of an arch VCPU request
defining API.

No functional change.

(Looks like x86 is running out of arch VCPU request bits.  Maybe
 someday we'll need to extend to 64.)
Signed-off-by: NAndrew Jones <drjones@redhat.com>
Acked-by: NChristoffer Dall <cdall@linaro.org>
Signed-off-by: NChristoffer Dall <cdall@linaro.org>

In some fio benchmarks, halt_poll_ns=400000 caused CPU utilization to
increase heavily even in cases where the performance improvement was
small.  In particular, bandwidth divided by CPU usage was as much as
60% lower.

To some extent this is the expected effect of the patch, and the
additional CPU utilization is only visible when running the
benchmarks.  However, halving the threshold also halves the extra
CPU utilization (from +30-130% to +20-70%) and has no negative
effect on performance.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

When KVM updates accessed/dirty bits, this hook can be used
to invoke an arch specific function that implements/emulates
dirty logging such as PML.
Signed-off-by: NBandan Das <bsd@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

We needed the lock to avoid racing with creation of the irqchip on x86. As
kvm_set_irq_routing() calls srcu_synchronize_expedited(), this lock
might be held for a longer time.

Let's introduce an arch specific callback to check if we can actually
add irq routes. For x86, all we have to do is check if we have an
irqchip in the kernel. We don't need kvm->lock at that point as the
irqchip is marked as inititalized only when actually fully created.
Reported-by: NSteve Rutherford <srutherford@google.com>
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Fixes: 1df6dded ("KVM: x86: race between KVM_SET_GSI_ROUTING and KVM_CREATE_IRQCHIP")
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

kvm_make_all_requests() provides a synchronization that waits until all
kicked VCPUs have acknowledged the kick.  This is important for
KVM_REQ_MMU_RELOAD as it prevents freeing while lockless paging is
underway.

This patch adds the synchronization property into all requests that are
currently being used with kvm_make_all_requests() in order to preserve
the current behavior and only introduce a new framework.  Removing it
from requests where it is not necessary is left for future patches.
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Some operations must ensure that the guest is not running with stale
data, but if the guest is halted, then the update can wait until another
event happens.  kvm_make_all_requests() currently doesn't wake up, so we
can mark all requests used with it.

First 8 bits were arbitrarily reserved for request numbers.

Most uses of requests have the request type as a constant, so a compiler
will optimize the '&'.

An alternative would be to have an inline function that would return
whether the request needs a wake-up or not, but I like this one better
even though it might produce worse assembly.
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Hardware support for faulting on the cpuid instruction is not required to
emulate it, because cpuid triggers a VM exit anyways. KVM handles the relevant
MSRs (MSR_PLATFORM_INFO and MSR_MISC_FEATURES_ENABLE) and upon a
cpuid-induced VM exit checks the cpuid faulting state and the CPL.
kvm_require_cpl is even kind enough to inject the GP fault for us.
Signed-off-by: NKyle Huey <khuey@kylehuey.com>
Reviewed-by: NDavid Matlack <dmatlack@google.com>
[Return "1" from kvm_emulate_cpuid, it's not void. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

Let's add a new mode and set it while we create the irqchip via
KVM_CREATE_IRQCHIP and KVM_CAP_SPLIT_IRQCHIP.

This mode will be used later to test if adding routes
(in kvm_set_routing_entry()) is already allowed.
Signed-off-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Its value has never changed; we might as well make it part of the ABI instead
of using the return value of KVM_CHECK_EXTENSION(KVM_CAP_COALESCED_MMIO).

Because PPC does not always make MMIO available, the code has to be made
dependent on CONFIG_KVM_MMIO rather than KVM_COALESCED_MMIO_PAGE_OFFSET.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>