Il 19/06/2014 13:17, "newtongao(??????)" ha scritto:
This is more concisely
From 6ddeb18347f9dda0fe37702e0d067a4129a89b54 Mon Sep 17 00:00:00 2001
From: Xiaoming Gao <newton...@tencent.com>
Date: Thu, 19 Jun 2014 19:14:57 +0800
Subject: [PATCH] kvm: fix hyperv tsc page clear wrong address
tsc page addr need clear the low HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT bits
before kvm_write_guest write the zero tsc_ref structure to guest, or it will
lead
guest to get wrong clocksource.
windows guest will get strong impact, QueryPerformanceCounter will always
return 0
,all things in windows rely on clock source, will in serious chaos.
Right, this can happen if Windows passes a non-zero page to KVM.
Thanks,
Paolo
Signed-off-by: Xiaoming Gao <newton...@tencnet.com>
---
arch/x86/kvm/x86.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f32a025..f644933 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1898,7 +1898,7 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32
msr, u64 data)
if (!(data & HV_X64_MSR_TSC_REFERENCE_ENABLE))
break;
gfn = data >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
- if (kvm_write_guest(kvm, data,
+ if (kvm_write_guest(kvm, gfn <<
HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT,
&tsc_ref, sizeof(tsc_ref)))
return 1;
mark_page_dirty(kvm, gfn);
--
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