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  1. 18 3月, 2021 1 次提交
    • V
      KVM: x86: hyper-v: Track Hyper-V TSC page status · cc9cfddb
      由 Vitaly Kuznetsov 提交于 
      Create an infrastructure for tracking Hyper-V TSC page status, i.e. if it
was updated from guest/host side or if we've failed to set it up (because
e.g. guest wrote some garbage to HV_X64_MSR_REFERENCE_TSC) and there's no
need to retry.

Also, in a hypothetical situation when we are in 'always catchup' mode for
TSC we can now avoid contending 'hv->hv_lock' on every guest enter by
setting the state to HV_TSC_PAGE_BROKEN after compute_tsc_page_parameters()
returns false.

Check for HV_TSC_PAGE_SET state instead of '!hv->tsc_ref.tsc_sequence' in
get_time_ref_counter() to properly handle the situation when we failed to
write the updated TSC page values to the guest.
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210316143736.964151-4-vkuznets@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      cc9cfddb
  3. 17 3月, 2021 2 次提交
  5. 26 2月, 2021 1 次提交
    • W
      KVM: x86: hyper-v: Fix Hyper-V context null-ptr-deref · 919f4ebc
      由 Wanpeng Li 提交于 
      Reported by syzkaller:

    KASAN: null-ptr-deref in range [0x0000000000000140-0x0000000000000147]
    CPU: 1 PID: 8370 Comm: syz-executor859 Not tainted 5.11.0-syzkaller #0
    RIP: 0010:synic_get arch/x86/kvm/hyperv.c:165 [inline]
    RIP: 0010:kvm_hv_set_sint_gsi arch/x86/kvm/hyperv.c:475 [inline]
    RIP: 0010:kvm_hv_irq_routing_update+0x230/0x460 arch/x86/kvm/hyperv.c:498
    Call Trace:
     kvm_set_irq_routing+0x69b/0x940 arch/x86/kvm/../../../virt/kvm/irqchip.c:223
     kvm_vm_ioctl+0x12d0/0x2800 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3959
     vfs_ioctl fs/ioctl.c:48 [inline]
     __do_sys_ioctl fs/ioctl.c:753 [inline]
     __se_sys_ioctl fs/ioctl.c:739 [inline]
     __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
     do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
     entry_SYSCALL_64_after_hwframe+0x44/0xae

Hyper-V context is lazily allocated until Hyper-V specific MSRs are accessed
or SynIC is enabled. However, the syzkaller testcase sets irq routing table
directly w/o enabling SynIC. This results in null-ptr-deref when accessing
SynIC Hyper-V context. This patch fixes it.

syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=163342ccd00000

Reported-by: syzbot+6987f3b2dbd9eda95f12@syzkaller.appspotmail.com
Fixes: 8f014550 ("KVM: x86: hyper-v: Make Hyper-V emulation enablement conditional")
Signed-off-by: NWanpeng Li <wanpengli@tencent.com>
Message-Id: <1614326399-5762-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      919f4ebc
  7. 09 2月, 2021 11 次提交
  9. 04 2月, 2021 2 次提交
    • J
      KVM: x86/xen: Fix coexistence of Xen and Hyper-V hypercalls · 79033beb
      由 Joao Martins 提交于 
      Disambiguate Xen vs. Hyper-V calls by adding 'orl $0x80000000, %eax'
at the start of the Hyper-V hypercall page when Xen hypercalls are
also enabled.

That bit is reserved in the Hyper-V ABI, and those hypercall numbers
will never be used by Xen (because it does precisely the same trick).

Switch to using kvm_vcpu_write_guest() while we're at it, instead of
open-coding it.
Signed-off-by: NDavid Woodhouse <dwmw@amazon.co.uk>
      79033beb
    • J
      KVM: x86: use static calls to reduce kvm_x86_ops overhead · b3646477
      由 Jason Baron 提交于 
      Convert kvm_x86_ops to use static calls. Note that all kvm_x86_ops are
covered here except for 'pmu_ops and 'nested ops'.

Here are some numbers running cpuid in a loop of 1 million calls averaged
over 5 runs, measured in the vm (lower is better).

Intel Xeon 3000MHz:

           |default    |mitigations=off
-------------------------------------
vanilla    |.671s      |.486s
static call|.573s(-15%)|.458s(-6%)

AMD EPYC 2500MHz:

           |default    |mitigations=off
-------------------------------------
vanilla    |.710s      |.609s
static call|.664s(-6%) |.609s(0%)

Cc: Paolo Bonzini <pbonzini@redhat.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>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: NJason Baron <jbaron@akamai.com>
Message-Id: <e057bf1b8a7ad15652df6eeba3f907ae758d3399.1610680941.git.jbaron@akamai.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      b3646477
  11. 15 11月, 2020 1 次提交
  13. 28 9月, 2020 2 次提交
  15. 27 9月, 2020 1 次提交
  17. 24 8月, 2020 1 次提交
  19. 11 8月, 2020 1 次提交
    • J
      x86/kvm/hyper-v: Synic default SCONTROL MSR needs to be enabled · 99b48ecc
      由 Jon Doron 提交于 
      Based on an analysis of the HyperV firmwares (Gen1 and Gen2) it seems
like the SCONTROL is not being set to the ENABLED state as like we have
thought.

Also from a test done by Vitaly Kuznetsov, running a nested HyperV it
was concluded that the first access to the SCONTROL MSR with a read
resulted with the value of 0x1, aka HV_SYNIC_CONTROL_ENABLE.

It's important to note that this diverges from the value states in the
HyperV TLFS of 0.
Signed-off-by: NJon Doron <arilou@gmail.com>
Message-Id: <20200717125238.1103096-2-arilou@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      99b48ecc
  21. 04 6月, 2020 1 次提交
  23. 01 6月, 2020 3 次提交
    • J
      x86/kvm/hyper-v: Add support for synthetic debugger via hypercalls · b187038b
      由 Jon Doron 提交于 
      There is another mode for the synthetic debugger which uses hypercalls
to send/recv network data instead of the MSR interface.

This interface is much slower and less recommended since you might get
a lot of VMExits while KDVM polling for new packets to recv, rather
than simply checking the pending page to see if there is data avialble
and then request.
Reviewed-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NJon Doron <arilou@gmail.com>
Message-Id: <20200529134543.1127440-6-arilou@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      b187038b
    • J
      x86/kvm/hyper-v: enable hypercalls regardless of hypercall page · 45c38973
      由 Jon Doron 提交于 
      Microsoft's kdvm.dll dbgtransport module does not respect the hypercall
page and simply identifies the CPU being used (AMD/Intel) and according
to it simply makes hypercalls with the relevant instruction
(vmmcall/vmcall respectively).

The relevant function in kdvm is KdHvConnectHypervisor which first checks
if the hypercall page has been enabled via HV_X64_MSR_HYPERCALL_ENABLE,
and in case it was not it simply sets the HV_X64_MSR_GUEST_OS_ID to
0x1000101010001 which means:
build_number = 0x0001
service_version = 0x01
minor_version = 0x01
major_version = 0x01
os_id = 0x00 (Undefined)
vendor_id = 1 (Microsoft)
os_type = 0 (A value of 0 indicates a proprietary, closed source OS)

and starts issuing the hypercall without setting the hypercall page.

To resolve this issue simply enable hypercalls also if the guest_os_id
is not 0.
Reviewed-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NJon Doron <arilou@gmail.com>
Message-Id: <20200529134543.1127440-5-arilou@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      45c38973
    • J
      x86/kvm/hyper-v: Add support for synthetic debugger interface · f97f5a56
      由 Jon Doron 提交于 
      Add support for Hyper-V synthetic debugger (syndbg) interface.
The syndbg interface is using MSRs to emulate a way to send/recv packets
data.

The debug transport dll (kdvm/kdnet) will identify if Hyper-V is enabled
and if it supports the synthetic debugger interface it will attempt to
use it, instead of trying to initialize a network adapter.
Reviewed-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NJon Doron <arilou@gmail.com>
Message-Id: <20200529134543.1127440-4-arilou@gmail.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      f97f5a56
  25. 20 5月, 2020 1 次提交
  27. 08 5月, 2020 1 次提交
  29. 23 4月, 2020 1 次提交
    • P
      KVM: x86: move nested-related kvm_x86_ops to a separate struct · 33b22172
      由 Paolo Bonzini 提交于 
      Clean up some of the patching of kvm_x86_ops, by moving kvm_x86_ops related to
nested virtualization into a separate struct.

As a result, these ops will always be non-NULL on VMX.  This is not a problem:

* check_nested_events is only called if is_guest_mode(vcpu) returns true

* get_nested_state treats VMXOFF state the same as nested being disabled

* set_nested_state fails if you attempt to set nested state while
  nesting is disabled

* nested_enable_evmcs could already be called on a CPU without VMX enabled
  in CPUID.

* nested_get_evmcs_version was fixed in the previous patch
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      33b22172
  31. 21 4月, 2020 1 次提交
  33. 31 3月, 2020 1 次提交
  35. 05 2月, 2020 1 次提交
  37. 28 1月, 2020 1 次提交
  39. 21 1月, 2020 2 次提交
  41. 09 1月, 2020 1 次提交
  43. 24 9月, 2019 2 次提交
    • V
      KVM: x86: hyper-v: set NoNonArchitecturalCoreSharing CPUID bit when SMT is impossible · b2d8b167
      由 Vitaly Kuznetsov 提交于 
      Hyper-V 2019 doesn't expose MD_CLEAR CPUID bit to guests when it cannot
guarantee that two virtual processors won't end up running on sibling SMT
threads without knowing about it. This is done as an optimization as in
this case there is nothing the guest can do to protect itself against MDS
and issuing additional flush requests is just pointless. On bare metal the
topology is known, however, when Hyper-V is running nested (e.g. on top of
KVM) it needs an additional piece of information: a confirmation that the
exposed topology (wrt vCPU placement on different SMT threads) is
trustworthy.

NoNonArchitecturalCoreSharing (CPUID 0x40000004 EAX bit 18) is described in
TLFS as follows: "Indicates that a virtual processor will never share a
physical core with another virtual processor, except for virtual processors
that are reported as sibling SMT threads." From KVM we can give such
guarantee in two cases:
- SMT is unsupported or forcefully disabled (just 'disabled' doesn't work
 as it can become re-enabled during the lifetime of the guest).
- vCPUs are properly pinned so the scheduler won't put them on sibling
SMT threads (when they're not reported as such).

This patch reports NoNonArchitecturalCoreSharing bit in to userspace in the
first case. The second case is outside of KVM's domain of responsibility
(as vCPU pinning is actually done by someone who manages KVM's userspace -
e.g. libvirt pinning QEMU threads).
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      b2d8b167
    • W
      KVM: hyperv: Fix Direct Synthetic timers assert an interrupt w/o lapic_in_kernel · a073d7e3
      由 Wanpeng Li 提交于 
      Reported by syzkaller:

	kasan: GPF could be caused by NULL-ptr deref or user memory access
	general protection fault: 0000 [#1] PREEMPT SMP KASAN
	RIP: 0010:__apic_accept_irq+0x46/0x740 arch/x86/kvm/lapic.c:1029
	Call Trace:
	kvm_apic_set_irq+0xb4/0x140 arch/x86/kvm/lapic.c:558
	stimer_notify_direct arch/x86/kvm/hyperv.c:648 [inline]
	stimer_expiration arch/x86/kvm/hyperv.c:659 [inline]
	kvm_hv_process_stimers+0x594/0x1650 arch/x86/kvm/hyperv.c:686
	vcpu_enter_guest+0x2b2a/0x54b0 arch/x86/kvm/x86.c:7896
	vcpu_run+0x393/0xd40 arch/x86/kvm/x86.c:8152
	kvm_arch_vcpu_ioctl_run+0x636/0x900 arch/x86/kvm/x86.c:8360
	kvm_vcpu_ioctl+0x6cf/0xaf0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2765

The testcase programs HV_X64_MSR_STIMERn_CONFIG/HV_X64_MSR_STIMERn_COUNT,
in addition, there is no lapic in the kernel, the counters value are small
enough in order that kvm_hv_process_stimers() inject this already-expired
timer interrupt into the guest through lapic in the kernel which triggers
the NULL deferencing. This patch fixes it by don't advertise direct mode
synthetic timers and discarding the inject when lapic is not in kernel.

syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=1752fe0a600000

Reported-by: syzbot+dff25ee91f0c7d5c1695@syzkaller.appspotmail.com
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NWanpeng Li <wanpengli@tencent.com>
Reviewed-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      a073d7e3
  45. 28 8月, 2019 1 次提交