| Message ID | 1450091277-26200-1-git-send-email-haozhong.zhang@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 14/12/2015 12:07, Haozhong Zhang wrote: > This patch fix a bug that prevents VM rebooting on recent versions of > KVM (from commit 9dbe6cf). > > kvm_get_msrs() is called to save guest MSR_TSC_AUX and other MSRs across > rebooting. It only checks whether KVM exposes MSR_TSC_AUX to userspace. > However, if vcpu does not support rdtscp (e.g. kvm64), current KVM will > fail the saving and thus all other MSRs following it will fail in > kvm_get_msrs(). As a result, from KVM commit 9dbe6cf that exposes > MSR_TSC_AUX, VM can not successfully reboot. > > This patch fixes this bug by adding the missing rdtscp feature checks. That commit is not in any released kernel. It's better if we just check msr_info->host_initiated in vmx_get_msr and vmx_set_msr. Can you prepare a patch? Thanks, Paolo > Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> > --- > target-i386/kvm.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/target-i386/kvm.c b/target-i386/kvm.c > index 6dc9846..cc842c6 100644 > --- a/target-i386/kvm.c > +++ b/target-i386/kvm.c > @@ -1414,7 +1414,8 @@ static int kvm_put_msrs(X86CPU *cpu, int level) > if (has_msr_hsave_pa) { > kvm_msr_entry_set(&msrs[n++], MSR_VM_HSAVE_PA, env->vm_hsave); > } > - if (has_msr_tsc_aux) { > + if (has_msr_tsc_aux && > + (env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP)) { > kvm_msr_entry_set(&msrs[n++], MSR_TSC_AUX, env->tsc_aux); > } > if (has_msr_tsc_adjust) { > @@ -1793,7 +1794,8 @@ static int kvm_get_msrs(X86CPU *cpu) > if (has_msr_hsave_pa) { > msrs[n++].index = MSR_VM_HSAVE_PA; > } > - if (has_msr_tsc_aux) { > + if (has_msr_tsc_aux && > + (env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP)) { > msrs[n++].index = MSR_TSC_AUX; > } > if (has_msr_tsc_adjust) { > This commit is not in any released kernel. It's better if we just check msr_info->host_initiated in vmx_get_msr and vmx_set_msr. Can you prepare a patch? Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 12/14/15 12:51, Paolo Bonzini wrote: > > > On 14/12/2015 12:07, Haozhong Zhang wrote: > > This patch fix a bug that prevents VM rebooting on recent versions of > > KVM (from commit 9dbe6cf). > > > > kvm_get_msrs() is called to save guest MSR_TSC_AUX and other MSRs across > > rebooting. It only checks whether KVM exposes MSR_TSC_AUX to userspace. > > However, if vcpu does not support rdtscp (e.g. kvm64), current KVM will > > fail the saving and thus all other MSRs following it will fail in > > kvm_get_msrs(). As a result, from KVM commit 9dbe6cf that exposes > > MSR_TSC_AUX, VM can not successfully reboot. > > > > This patch fixes this bug by adding the missing rdtscp feature checks. > > That commit is not in any released kernel. Right, it's currently only in kvm next. But I assume it would finally come into a released kernel. > It's better if we just check > msr_info->host_initiated in vmx_get_msr and vmx_set_msr. Can you prepare > a patch? > Yes, I'll send a KVM patch later. And then this QEMU patch is not needed any more. Haozhong -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 14/12/2015 14:54, Haozhong Zhang wrote: >> > That commit is not in any released kernel. > Right, it's currently only in kvm next. But I assume it would finally come > into a released kernel. Yes, but until it is, it's easier (and better) to fix KVM instead of QEMU. > > It's better if we just check > > msr_info->host_initiated in vmx_get_msr and vmx_set_msr. Can you prepare > > a patch? > > Yes, I'll send a KVM patch later. And then this QEMU patch is not > needed any more. Great, thanks. paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 6dc9846..cc842c6 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -1414,7 +1414,8 @@ static int kvm_put_msrs(X86CPU *cpu, int level) if (has_msr_hsave_pa) { kvm_msr_entry_set(&msrs[n++], MSR_VM_HSAVE_PA, env->vm_hsave); } - if (has_msr_tsc_aux) { + if (has_msr_tsc_aux && + (env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP)) { kvm_msr_entry_set(&msrs[n++], MSR_TSC_AUX, env->tsc_aux); } if (has_msr_tsc_adjust) { @@ -1793,7 +1794,8 @@ static int kvm_get_msrs(X86CPU *cpu) if (has_msr_hsave_pa) { msrs[n++].index = MSR_VM_HSAVE_PA; } - if (has_msr_tsc_aux) { + if (has_msr_tsc_aux && + (env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP)) { msrs[n++].index = MSR_TSC_AUX; } if (has_msr_tsc_adjust) {
This patch fix a bug that prevents VM rebooting on recent versions of KVM (from commit 9dbe6cf). kvm_get_msrs() is called to save guest MSR_TSC_AUX and other MSRs across rebooting. It only checks whether KVM exposes MSR_TSC_AUX to userspace. However, if vcpu does not support rdtscp (e.g. kvm64), current KVM will fail the saving and thus all other MSRs following it will fail in kvm_get_msrs(). As a result, from KVM commit 9dbe6cf that exposes MSR_TSC_AUX, VM can not successfully reboot. This patch fixes this bug by adding the missing rdtscp feature checks. Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> --- target-i386/kvm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)