Message ID | 20201007102032.98565-1-roger.pau@citrix.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | x86/msr: handle IA32_THERM_STATUS | expand |
On 07.10.2020 12:20, Roger Pau Monne wrote: > Windows 8 will attempt to read MSR_IA32_THERM_STATUS and panic if a > #GP fault is injected as a result: > > vmx.c:3035:d8v0 RDMSR 0x0000019c unimplemented > d8v0 VIRIDIAN CRASH: 3b c0000096 fffff8061de31651 fffff4088a613720 0 > > So handle the MSR and return 0 instead. > > Note that this is done on the generic MSR handler, and PV guest will > also get 0 back when trying to read the MSR. There doesn't seem to be > much value in handling the MSR for HVM guests only. > > Fixes: 84e848fd7a1 ('x86/hvm: disallow access to unknown MSRs') > Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com>
On 07.10.2020 12:20, Roger Pau Monne wrote: > --- a/xen/arch/x86/msr.c > +++ b/xen/arch/x86/msr.c > @@ -253,6 +253,12 @@ int guest_rdmsr(struct vcpu *v, uint32_t msr, uint64_t *val) > break; > goto gp_fault; > > + case MSR_IA32_THERM_STATUS: > + if ( cp->x86_vendor != X86_VENDOR_INTEL ) > + goto gp_fault; > + *val = 0; > + break; I've been puzzled while applying this: The upper patch context doesn't match what's been in master for about the last month, and hence I wonder what version of the tree you created this patch against. In any event please double check that I didn't screw it up. Jan
On Wed, Oct 14, 2020 at 02:17:15PM +0200, Jan Beulich wrote: > On 07.10.2020 12:20, Roger Pau Monne wrote: > > --- a/xen/arch/x86/msr.c > > +++ b/xen/arch/x86/msr.c > > @@ -253,6 +253,12 @@ int guest_rdmsr(struct vcpu *v, uint32_t msr, uint64_t *val) > > break; > > goto gp_fault; > > > > + case MSR_IA32_THERM_STATUS: > > + if ( cp->x86_vendor != X86_VENDOR_INTEL ) > > + goto gp_fault; > > + *val = 0; > > + break; > > I've been puzzled while applying this: The upper patch context doesn't > match what's been in master for about the last month, and hence I > wonder what version of the tree you created this patch against. In any > event please double check that I didn't screw it up. I had this applied on top of: https://lore.kernel.org/xen-devel/20201006162327.93055-1-roger.pau@citrix.com/ Which I will reply to now because I'm not sure how to proceed there. Thanks for fixing the context and applied. Roger.
diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c index e4c4fa6127..190d6ac6c5 100644 --- a/xen/arch/x86/msr.c +++ b/xen/arch/x86/msr.c @@ -253,6 +253,12 @@ int guest_rdmsr(struct vcpu *v, uint32_t msr, uint64_t *val) break; goto gp_fault; + case MSR_IA32_THERM_STATUS: + if ( cp->x86_vendor != X86_VENDOR_INTEL ) + goto gp_fault; + *val = 0; + break; + case MSR_X2APIC_FIRST ... MSR_X2APIC_LAST: if ( !is_hvm_domain(d) || v != curr ) goto gp_fault;
Windows 8 will attempt to read MSR_IA32_THERM_STATUS and panic if a #GP fault is injected as a result: vmx.c:3035:d8v0 RDMSR 0x0000019c unimplemented d8v0 VIRIDIAN CRASH: 3b c0000096 fffff8061de31651 fffff4088a613720 0 So handle the MSR and return 0 instead. Note that this is done on the generic MSR handler, and PV guest will also get 0 back when trying to read the MSR. There doesn't seem to be much value in handling the MSR for HVM guests only. Fixes: 84e848fd7a1 ('x86/hvm: disallow access to unknown MSRs') Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> --- xen/arch/x86/msr.c | 6 ++++++ 1 file changed, 6 insertions(+)