| Message ID | BLU436-SMTP38EADC8B6CF4CB3F41B0A580380@phx.gbl (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Ping, :-) On 10/21/15 2:28 PM, Wanpeng Li wrote: > Reference SDM 3.4.3: > > Following initialization of the processor (either by asserting the > RESET pin or the INIT pin), the state of the EFLAGS register is > 00000002H. > > However, the eflags fixed bit is not set and other bits are also not > cleared during the init/reset in kvm. > > This patch fix it by set eflags register to 00000002H following > initialization of the processor. > > Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> > --- > arch/x86/kvm/vmx.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index b680c2e..326f6ea 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -4935,6 +4935,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) > vmx_set_efer(vcpu, 0); > vmx_fpu_activate(vcpu); > update_exception_bitmap(vcpu); > + vmx_set_rflags(vcpu, X86_EFLAGS_FIXED); > > vpid_sync_context(vmx->vpid); > } -- 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
Here are my 5 cents. Note that vmx_vcpu_reset calls: vmcs_writel(GUEST_RFLAGS, 0x02); (And the RFLAGS value is not cached by KVM, so no consistency problem should occur.) You may want to change the value into constant or call a wrapper function for setting RFLAGS, but I don’t see something broken in the functionality. Regards, Nadav Wanpeng Li <wanpeng.li@hotmail.com> wrote: > Ping, :-) > On 10/21/15 2:28 PM, Wanpeng Li wrote: >> Reference SDM 3.4.3: >> >> Following initialization of the processor (either by asserting the >> RESET pin or the INIT pin), the state of the EFLAGS register is >> 00000002H. >> >> However, the eflags fixed bit is not set and other bits are also not >> cleared during the init/reset in kvm. >> >> This patch fix it by set eflags register to 00000002H following >> initialization of the processor. >> >> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> >> --- >> arch/x86/kvm/vmx.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >> index b680c2e..326f6ea 100644 >> --- a/arch/x86/kvm/vmx.c >> +++ b/arch/x86/kvm/vmx.c >> @@ -4935,6 +4935,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) >> vmx_set_efer(vcpu, 0); >> vmx_fpu_activate(vcpu); >> update_exception_bitmap(vcpu); >> + vmx_set_rflags(vcpu, X86_EFLAGS_FIXED); >> vpid_sync_context(vmx->vpid); >> } > > -- > 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 -- 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 28/10/2015 09:10, Nadav Amit wrote: > Here are my 5 cents. Note that vmx_vcpu_reset calls: > > vmcs_writel(GUEST_RFLAGS, 0x02); > > (And the RFLAGS value is not cached by KVM, so no consistency problem should > occur.) > > You may want to change the value into constant or call a wrapper function > for setting RFLAGS, but I don’t see something broken in the functionality. I agree. Wanpeng, if this is just a cleanup, can you send v2 that removes or modifies the existing call to vmcs_writel? If there is a bug, can you write a unit test for it? It should be possible to test for the problem using INIT+SIPI on an AP. Thanks, Paolo > Regards, > Nadav > > Wanpeng Li <wanpeng.li@hotmail.com> wrote: > >> Ping, :-) >> On 10/21/15 2:28 PM, Wanpeng Li wrote: >>> Reference SDM 3.4.3: >>> >>> Following initialization of the processor (either by asserting the >>> RESET pin or the INIT pin), the state of the EFLAGS register is >>> 00000002H. >>> >>> However, the eflags fixed bit is not set and other bits are also not >>> cleared during the init/reset in kvm. >>> >>> This patch fix it by set eflags register to 00000002H following >>> initialization of the processor. >>> >>> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> >>> --- >>> arch/x86/kvm/vmx.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >>> index b680c2e..326f6ea 100644 >>> --- a/arch/x86/kvm/vmx.c >>> +++ b/arch/x86/kvm/vmx.c >>> @@ -4935,6 +4935,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) >>> vmx_set_efer(vcpu, 0); >>> vmx_fpu_activate(vcpu); >>> update_exception_bitmap(vcpu); >>> + vmx_set_rflags(vcpu, X86_EFLAGS_FIXED); >>> vpid_sync_context(vmx->vpid); >>> } >> >> -- >> 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 > > -- 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
2015-11-03 18:47 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>: > > > On 28/10/2015 09:10, Nadav Amit wrote: >> Here are my 5 cents. Note that vmx_vcpu_reset calls: >> >> vmcs_writel(GUEST_RFLAGS, 0x02); >> >> (And the RFLAGS value is not cached by KVM, so no consistency problem should >> occur.) >> >> You may want to change the value into constant or call a wrapper function >> for setting RFLAGS, but I don’t see something broken in the functionality. > > I agree. Wanpeng, if this is just a cleanup, can you send v2 that > removes or modifies the existing call to vmcs_writel? If there is a > bug, can you write a unit test for it? It should be possible to test > for the problem using INIT+SIPI on an AP. You are right, I write a INIT+SIPI kvm-unit-test and didn't trigger any bug. Please ignore the patch. Regards, Wanpeng Li -- 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 b680c2e..326f6ea 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -4935,6 +4935,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) vmx_set_efer(vcpu, 0); vmx_fpu_activate(vcpu); update_exception_bitmap(vcpu); + vmx_set_rflags(vcpu, X86_EFLAGS_FIXED); vpid_sync_context(vmx->vpid); }
Reference SDM 3.4.3: Following initialization of the processor (either by asserting the RESET pin or the INIT pin), the state of the EFLAGS register is 00000002H. However, the eflags fixed bit is not set and other bits are also not cleared during the init/reset in kvm. This patch fix it by set eflags register to 00000002H following initialization of the processor. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> --- arch/x86/kvm/vmx.c | 1 + 1 file changed, 1 insertion(+)