Skip to content

K
Kernel

openeuler / Kernel
1 年多 前同步成功

通知 8
Star 0
Fork 0
K
Kernel
切换分支/标签
  1. 16 4月, 2018 1 次提交
  3. 13 4月, 2018 2 次提交
  5. 11 4月, 2018 2 次提交
  7. 10 4月, 2018 2 次提交
    • C
      kvm: selftests: fix spelling mistake: "divisable" and "divisible" · 4d5f26ee
      由 Colin Ian King 提交于 
      Trivial fix to spelling mistakes in comment and message text
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      4d5f26ee
    • K
      X86/VMX: Disable VMX preemption timer if MWAIT is not intercepted · 386c6ddb
      由 KarimAllah Ahmed 提交于 
      The VMX-preemption timer is used by KVM as a way to set deadlines for the
guest (i.e. timer emulation). That was safe till very recently when
capability KVM_X86_DISABLE_EXITS_MWAIT to disable intercepting MWAIT was
introduced. According to Intel SDM 25.5.1:

"""
The VMX-preemption timer operates in the C-states C0, C1, and C2; it also
operates in the shutdown and wait-for-SIPI states. If the timer counts down
to zero in any state other than the wait-for SIPI state, the logical
processor transitions to the C0 C-state and causes a VM exit; the timer
does not cause a VM exit if it counts down to zero in the wait-for-SIPI
state. The timer is not decremented in C-states deeper than C2.
"""

Now once the guest issues the MWAIT with a c-state deeper than
C2 the preemption timer will never wake it up again since it stopped
ticking! Usually this is compensated by other activities in the system that
would wake the core from the deep C-state (and cause a VMExit). For
example, if the host itself is ticking or it received interrupts, etc!

So disable the VMX-preemption timer if MWAIT is exposed to the guest!

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Signed-off-by: NKarimAllah Ahmed <karahmed@amazon.de>
Fixes: 4d5422ceSigned-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      386c6ddb
  9. 07 4月, 2018 1 次提交
  11. 05 4月, 2018 9 次提交
    • P
      kvm: selftests: add sync_regs_test · 6089ae0b
      由 Paolo Bonzini 提交于 
      This includes the infrastructure to map the test into the guest and
run code from the test program inside a VM.
Signed-off-by: NKen Hofsass <hofsass@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      6089ae0b
    • P
      kvm: selftests: add API testing infrastructure · 783e9e51
      由 Paolo Bonzini 提交于 
      Testsuite contributed by Google and cleaned up by myself for
inclusion in Linux.
Signed-off-by: NKen Hofsass <hofsass@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      783e9e51
    • P
      kvm: x86: fix a compile warning · 3140c156
      由 Peng Hao 提交于 
      fix a "warning: no previous prototype".

Cc: stable@vger.kernel.org
Signed-off-by: NPeng Hao <peng.hao2@zte.com.cn>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      3140c156
    • W
      KVM: X86: Add Force Emulation Prefix for "emulate the next instruction" · 6c86eedc
      由 Wanpeng Li 提交于 
      There is no easy way to force KVM to run an instruction through the emulator
(by design as that will expose the x86 emulator as a significant attack-surface).
However, we do wish to expose the x86 emulator in case we are testing it
(e.g. via kvm-unit-tests). Therefore, this patch adds a "force emulation prefix"
that is designed to raise #UD which KVM will trap and it's #UD exit-handler will
match "force emulation prefix" to run instruction after prefix by the x86 emulator.
To not expose the x86 emulator by default, we add a module parameter that should
be off by default.

A simple testcase here:

    #include <stdio.h>
    #include <string.h>

    #define HYPERVISOR_INFO 0x40000000

    #define CPUID(idx, eax, ebx, ecx, edx) \
        asm volatile (\
        "ud2a; .ascii \"kvm\"; cpuid" \
        :"=b" (*ebx), "=a" (*eax), "=c" (*ecx), "=d" (*edx) \
            :"0"(idx) );

    void main()
    {
        unsigned int eax, ebx, ecx, edx;
        char string[13];

        CPUID(HYPERVISOR_INFO, &eax, &ebx, &ecx, &edx);
        *(unsigned int *)(string + 0) = ebx;
        *(unsigned int *)(string + 4) = ecx;
        *(unsigned int *)(string + 8) = edx;

        string[12] = 0;
        if (strncmp(string, "KVMKVMKVM\0\0\0", 12) == 0)
            printf("kvm guest\n");
        else
            printf("bare hardware\n");
    }
Suggested-by: NAndrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Reviewed-by: NLiran Alon <liran.alon@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: NWanpeng Li <wanpengli@tencent.com>
[Correctly handle usermode exits. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      6c86eedc
    • W
      KVM: X86: Introduce handle_ud() · 082d06ed
      由 Wanpeng Li 提交于 
      Introduce handle_ud() to handle invalid opcode, this function will be
used by later patches.
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: NLiran Alon <liran.alon@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim KrÄmář <rkrcmar@redhat.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: NWanpeng Li <wanpengli@tencent.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      082d06ed
    • P
      KVM: vmx: unify adjacent #ifdefs · 4fde8d57
      由 Paolo Bonzini 提交于 
      vmx_save_host_state has multiple ifdefs for CONFIG_X86_64 that have
no other code between them.  Simplify by reducing them to a single
conditional.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      4fde8d57
    • A
      x86: kvm: hide the unused 'cpu' variable · 51e8a8cc
      由 Arnd Bergmann 提交于 
      The local variable was newly introduced but is only accessed in one
place on x86_64, but not on 32-bit:

arch/x86/kvm/vmx.c: In function 'vmx_save_host_state':
arch/x86/kvm/vmx.c:2175:6: error: unused variable 'cpu' [-Werror=unused-variable]

This puts it into another #ifdef.

Fixes: 35060ed6 ("x86/kvm/vmx: avoid expensive rdmsr for MSR_GS_BASE")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      51e8a8cc
    • S
      KVM: VMX: remove bogus WARN_ON in handle_ept_misconfig · c75d0edc
      由 Sean Christopherson 提交于 
      Remove the WARN_ON in handle_ept_misconfig() as it is unnecessary
and causes false positives.  Return the unmodified result of
kvm_mmu_page_fault() instead of converting a system error code to
KVM_EXIT_UNKNOWN so that userspace sees the error code of the
actual failure, not a generic "we don't know what went wrong".

  * kvm_mmu_page_fault() will WARN if reserved bits are set in the
    SPTEs, i.e. it covers the case where an EPT misconfig occurred
    because of a KVM bug.

  * The WARN_ON will fire on any system error code that is hit while
    handling the fault, e.g. -ENOMEM from mmu_topup_memory_caches()
    while handling a legitmate MMIO EPT misconfig or -EFAULT from
    kvm_handle_bad_page() if the corresponding HVA is invalid.  In
    either case, userspace should receive the original error code
    and firing a warning is incorrect behavior as KVM is operating
    as designed.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      c75d0edc
    • S
      Revert "KVM: X86: Fix SMRAM accessing even if VM is shutdown" · 2c151b25
      由 Sean Christopherson 提交于 
      The bug that led to commit 95e057e2
was a benign warning (no adverse affects other than the warning
itself) that was detected by syzkaller.  Further inspection shows
that the WARN_ON in question, in handle_ept_misconfig(), is
unnecessary and flawed (this was also briefly discussed in the
original patch: https://patchwork.kernel.org/patch/10204649).

  * The WARN_ON is unnecessary as kvm_mmu_page_fault() will WARN
    if reserved bits are set in the SPTEs, i.e. it covers the case
    where an EPT misconfig occurred because of a KVM bug.

  * The WARN_ON is flawed because it will fire on any system error
    code that is hit while handling the fault, e.g. -ENOMEM can be
    returned by mmu_topup_memory_caches() while handling a legitmate
    MMIO EPT misconfig.

The original behavior of returning -EFAULT when userspace munmaps
an HVA without first removing the memslot is correct and desirable,
i.e. KVM is letting userspace know it has generated a bad address.
Returning RET_PF_EMULATE masks the WARN_ON in the EPT misconfig path,
but does not fix the underlying bug, i.e. the WARN_ON is bogus.

Furthermore, returning RET_PF_EMULATE has the unwanted side effect of
causing KVM to attempt to emulate an instruction on any page fault
with an invalid HVA translation, e.g. a not-present EPT violation
on a VM_PFNMAP VMA whose fault handler failed to insert a PFN.

  * There is no guarantee that the fault is directly related to the
    instruction, i.e. the fault could have been triggered by a side
    effect memory access in the guest, e.g. while vectoring a #DB or
    writing a tracing record.  This could cause KVM to effectively
    mask the fault if KVM doesn't model the behavior leading to the
    fault, i.e. emulation could succeed and resume the guest.

  * If emulation does fail, KVM will return EMULATION_FAILED instead
    of -EFAULT, which is a red herring as the user will either debug
    a bogus emulation attempt or scratch their head wondering why we
    were attempting emulation in the first place.

TL;DR: revert to returning -EFAULT and remove the bogus WARN_ON in
handle_ept_misconfig in a future patch.

This reverts commit 95e057e2.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      2c151b25
  13. 04 4月, 2018 2 次提交
    • S
      kvm: Add emulation for movups/movupd · 29916968
      由 Stefan Fritsch 提交于 
      This is very similar to the aligned versions movaps/movapd.

We have seen the corresponding emulation failures with openbsd as guest
and with Windows 10 with intel HD graphics pass through.
Signed-off-by: NChristian Ehrhardt <christian_ehrhardt@genua.de>
Signed-off-by: NStefan Fritsch <sf@sfritsch.de>
Reviewed-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      29916968
    • S
      KVM: VMX: raise internal error for exception during invalid protected mode state · add5ff7a
      由 Sean Christopherson 提交于 
      Exit to userspace with KVM_INTERNAL_ERROR_EMULATION if we encounter
an exception in Protected Mode while emulating guest due to invalid
guest state.  Unlike Big RM, KVM doesn't support emulating exceptions
in PM, i.e. PM exceptions are always injected via the VMCS.  Because
we will never do VMRESUME due to emulation_required, the exception is
never realized and we'll keep emulating the faulting instruction over
and over until we receive a signal.

Exit to userspace iff there is a pending exception, i.e. don't exit
simply on a requested event. The purpose of this check and exit is to
aid in debugging a guest that is in all likelihood already doomed.
Invalid guest state in PM is extremely limited in normal operation,
e.g. it generally only occurs for a few instructions early in BIOS,
and any exception at this time is all but guaranteed to be fatal.
Non-vectored interrupts, e.g. INIT, SIPI and SMI, can be cleanly
handled/emulated, while checking for vectored interrupts, e.g. INTR
and NMI, without hitting false positives would add a fair amount of
complexity for almost no benefit (getting hit by lightning seems
more likely than encountering this specific scenario).

Add a WARN_ON_ONCE to vmx_queue_exception() if we try to inject an
exception via the VMCS and emulation_required is true.
Signed-off-by: NSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>
      add5ff7a
  15. 30 3月, 2018 1 次提交
  17. 29 3月, 2018 20 次提交