| Message ID | 20200907103143.58845-3-roger.pau@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86: switch default MSR behavior | expand |
On 07.09.2020 12:31, Roger Pau Monne wrote: > Linux PV guests will attempt to read the FEATURE_CONTROL MSR, so move > the handling done in VMX code into guest_rdmsr as it can be shared > between PV and HVM guests that way. > > Note that there's a slight behavior change and attempting to read the > MSR when no features are available will result in a fault. > > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com>
> From: Roger Pau Monne <roger.pau@citrix.com> > Sent: Monday, September 7, 2020 6:32 PM > > Linux PV guests will attempt to read the FEATURE_CONTROL MSR, so move > the handling done in VMX code into guest_rdmsr as it can be shared > between PV and HVM guests that way. > > Note that there's a slight behavior change and attempting to read the > MSR when no features are available will result in a fault. > > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> > --- > Changes since v3: > - Only allow reading the MSR when there are bits available (different > than bit 0). > > Changes from v1: > - Move the VMX implementation into guest_rdmsr. > --- > xen/arch/x86/hvm/vmx/vmx.c | 8 +------- > xen/arch/x86/msr.c | 12 ++++++++++++ > 2 files changed, 13 insertions(+), 7 deletions(-) > > diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c > index c4b40bf3cb..709ea149d1 100644 > --- a/xen/arch/x86/hvm/vmx/vmx.c > +++ b/xen/arch/x86/hvm/vmx/vmx.c > @@ -2980,13 +2980,7 @@ static int vmx_msr_read_intercept(unsigned int > msr, uint64_t *msr_content) > case MSR_IA32_DEBUGCTLMSR: > __vmread(GUEST_IA32_DEBUGCTL, msr_content); > break; > - case MSR_IA32_FEATURE_CONTROL: > - *msr_content = IA32_FEATURE_CONTROL_LOCK; > - if ( vmce_has_lmce(curr) ) > - *msr_content |= IA32_FEATURE_CONTROL_LMCE_ON; > - if ( nestedhvm_enabled(curr->domain) ) > - *msr_content |= > IA32_FEATURE_CONTROL_ENABLE_VMXON_OUTSIDE_SMX; > - break; > + > case MSR_IA32_VMX_BASIC...MSR_IA32_VMX_VMFUNC: > if ( !nvmx_msr_read_intercept(msr, msr_content) ) > goto gp_fault; > diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c > index 74bf7d9589..79fbb9e940 100644 > --- a/xen/arch/x86/msr.c > +++ b/xen/arch/x86/msr.c > @@ -25,6 +25,7 @@ > #include <xen/sched.h> > > #include <asm/debugreg.h> > +#include <asm/hvm/nestedhvm.h> > #include <asm/hvm/viridian.h> > #include <asm/msr.h> > #include <asm/setup.h> > @@ -197,6 +198,17 @@ int guest_rdmsr(struct vcpu *v, uint32_t msr, > uint64_t *val) > /* Not offered to guests. */ > goto gp_fault; > > + case MSR_IA32_FEATURE_CONTROL: > + if ( !cp->basic.vmx && !vmce_has_lmce(v) ) > + goto gp_fault; > + > + *val = IA32_FEATURE_CONTROL_LOCK; > + if ( vmce_has_lmce(v) ) > + *val |= IA32_FEATURE_CONTROL_LMCE_ON; > + if ( cp->basic.vmx ) > + *val |= IA32_FEATURE_CONTROL_ENABLE_VMXON_OUTSIDE_SMX; > + break; > + > case MSR_IA32_PLATFORM_ID: > if ( !(cp->x86_vendor & X86_VENDOR_INTEL) || > !(boot_cpu_data.x86_vendor & X86_VENDOR_INTEL) ) > -- > 2.28.0
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c index c4b40bf3cb..709ea149d1 100644 --- a/xen/arch/x86/hvm/vmx/vmx.c +++ b/xen/arch/x86/hvm/vmx/vmx.c @@ -2980,13 +2980,7 @@ static int vmx_msr_read_intercept(unsigned int msr, uint64_t *msr_content) case MSR_IA32_DEBUGCTLMSR: __vmread(GUEST_IA32_DEBUGCTL, msr_content); break; - case MSR_IA32_FEATURE_CONTROL: - *msr_content = IA32_FEATURE_CONTROL_LOCK; - if ( vmce_has_lmce(curr) ) - *msr_content |= IA32_FEATURE_CONTROL_LMCE_ON; - if ( nestedhvm_enabled(curr->domain) ) - *msr_content |= IA32_FEATURE_CONTROL_ENABLE_VMXON_OUTSIDE_SMX; - break; + case MSR_IA32_VMX_BASIC...MSR_IA32_VMX_VMFUNC: if ( !nvmx_msr_read_intercept(msr, msr_content) ) goto gp_fault; diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c index 74bf7d9589..79fbb9e940 100644 --- a/xen/arch/x86/msr.c +++ b/xen/arch/x86/msr.c @@ -25,6 +25,7 @@ #include <xen/sched.h> #include <asm/debugreg.h> +#include <asm/hvm/nestedhvm.h> #include <asm/hvm/viridian.h> #include <asm/msr.h> #include <asm/setup.h> @@ -197,6 +198,17 @@ int guest_rdmsr(struct vcpu *v, uint32_t msr, uint64_t *val) /* Not offered to guests. */ goto gp_fault; + case MSR_IA32_FEATURE_CONTROL: + if ( !cp->basic.vmx && !vmce_has_lmce(v) ) + goto gp_fault; + + *val = IA32_FEATURE_CONTROL_LOCK; + if ( vmce_has_lmce(v) ) + *val |= IA32_FEATURE_CONTROL_LMCE_ON; + if ( cp->basic.vmx ) + *val |= IA32_FEATURE_CONTROL_ENABLE_VMXON_OUTSIDE_SMX; + break; + case MSR_IA32_PLATFORM_ID: if ( !(cp->x86_vendor & X86_VENDOR_INTEL) || !(boot_cpu_data.x86_vendor & X86_VENDOR_INTEL) )
Linux PV guests will attempt to read the FEATURE_CONTROL MSR, so move the handling done in VMX code into guest_rdmsr as it can be shared between PV and HVM guests that way. Note that there's a slight behavior change and attempting to read the MSR when no features are available will result in a fault. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> --- Changes since v3: - Only allow reading the MSR when there are bits available (different than bit 0). Changes from v1: - Move the VMX implementation into guest_rdmsr. --- xen/arch/x86/hvm/vmx/vmx.c | 8 +------- xen/arch/x86/msr.c | 12 ++++++++++++ 2 files changed, 13 insertions(+), 7 deletions(-)