On Sun, Jan 17, 2010 at 02:49:30PM +0200, Avi Kivity wrote:
> On 01/17/2010 02:44 PM, Gleb Natapov wrote:
> >On Sun, Jan 17, 2010 at 02:10:45PM +0200, Avi Kivity wrote:
> >>On 01/17/2010 11:03 AM, Gleb Natapov wrote:
> >>>Minimum HYPER-V implementation should have GUEST_OS_ID, HYPERCALL and
> >>>VP_INDEX MSRs.
> >>>
> >>>
> >>> TRACE_EVENT(kvm_pio,
> >>>diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> >>>index 4d835b6..db0b2b1 100644
> >>>--- a/arch/x86/kvm/x86.c
> >>>+++ b/arch/x86/kvm/x86.c
> >>>@@ -630,7 +630,8 @@ static u32 msrs_to_save[] = {
> >>> #ifdef CONFIG_X86_64
> >>> MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR,
> >>> #endif
> >>>- MSR_IA32_TSC, MSR_IA32_PERF_STATUS, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA
> >>>+ MSR_IA32_TSC, MSR_IA32_PERF_STATUS, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
> >>>+ HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
> >>> };
> >>These will be disabled since the msrs don't exist on the host. See
> >>the comment above and KVM_SAVE_MSRS_BEGIN.
> >>
> >I see. Why not have two arrays?
>
> Clearly better.
>
> >>>+ case HV_X64_MSR_HYPERCALL: {
> >>>+ u64 gfn;
> >>>+ unsigned long addr;
> >>>+ /* if guest os id is not set hypercall should remain disabled */
> >>>+ if (!kvm->arch.hv_guest_os_id&& data)
> >>>+ break;
> >>>+ kvm->arch.hv_hypercall = data;
> >>>+ if (!kvm_hv_hypercall_enabled(kvm))
> >>>+ break;
> >>>+ gfn = kvm->arch.hv_hypercall>>
> >>>+ HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_SHIFT;
> >>>+ addr = gfn_to_hva(kvm, gfn);
> >>>+ if (kvm_is_error_hva(addr))
> >>>+ return 1;
> >>Should di the error check before assigning, perhaps.
> >>
> >Spec doesn't tell. And guest will get #GP and BSOD anyway.
>
> Well, all msrs I know of either #GP, or store the value and do what
> they're supposed to do, never both.
>
>
Make sense. Will fix.
--
Gleb.
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