| Message ID | 47a9cf4ebc3fde90fab06d54f32a225db9f0271c.1412727302.git.luto@amacapital.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Oct 7, 2014 at 5:16 PM, Andy Lutomirski <luto@amacapital.net> wrote: > CR4.TSD is guest-owned; don't trap writes to it in VMX guests. This > avoids a VM exit on context switches into or out of a PR_TSC_SIGSEGV > task. Friendly ping. I suspect this got lost in KVM Forum, etc. --Andy > > I think that this fixes an unintentional side-effect of: > 4c38609ac569 KVM: VMX: Make guest cr4 mask more conservative > > Signed-off-by: Andy Lutomirski <luto@amacapital.net> > --- > arch/x86/kvm/vmx.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 54ca301f8415..0653233fcc82 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -105,7 +105,7 @@ module_param(nested, bool, S_IRUGO); > (KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST | X86_CR0_PG | X86_CR0_PE) > #define KVM_CR4_GUEST_OWNED_BITS \ > (X86_CR4_PVI | X86_CR4_DE | X86_CR4_PCE | X86_CR4_OSFXSR \ > - | X86_CR4_OSXMMEXCPT) > + | X86_CR4_OSXMMEXCPT | X86_CR4_TSD) > > #define KVM_PMODE_VM_CR4_ALWAYS_ON (X86_CR4_PAE | X86_CR4_VMXE) > #define KVM_RMODE_VM_CR4_ALWAYS_ON (X86_CR4_VME | X86_CR4_PAE | X86_CR4_VMXE) > -- > 1.9.3 >
On 10/22/2014 09:10 PM, Andy Lutomirski wrote: > On Tue, Oct 7, 2014 at 5:16 PM, Andy Lutomirski <luto@amacapital.net> wrote: >> CR4.TSD is guest-owned; don't trap writes to it in VMX guests. This >> avoids a VM exit on context switches into or out of a PR_TSC_SIGSEGV >> task. > > Friendly ping. I suspect this got lost in KVM Forum, etc. Yup, will push tomorrow. 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/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 54ca301f8415..0653233fcc82 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -105,7 +105,7 @@ module_param(nested, bool, S_IRUGO); (KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST | X86_CR0_PG | X86_CR0_PE) #define KVM_CR4_GUEST_OWNED_BITS \ (X86_CR4_PVI | X86_CR4_DE | X86_CR4_PCE | X86_CR4_OSFXSR \ - | X86_CR4_OSXMMEXCPT) + | X86_CR4_OSXMMEXCPT | X86_CR4_TSD) #define KVM_PMODE_VM_CR4_ALWAYS_ON (X86_CR4_PAE | X86_CR4_VMXE) #define KVM_RMODE_VM_CR4_ALWAYS_ON (X86_CR4_VME | X86_CR4_PAE | X86_CR4_VMXE)
CR4.TSD is guest-owned; don't trap writes to it in VMX guests. This avoids a VM exit on context switches into or out of a PR_TSC_SIGSEGV task. I think that this fixes an unintentional side-effect of: 4c38609ac569 KVM: VMX: Make guest cr4 mask more conservative Signed-off-by: Andy Lutomirski <luto@amacapital.net> --- arch/x86/kvm/vmx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)