| Message ID | 147377817920.11859.9423132506504837623.stgit@brijesh-build-machine |
|---|---|
| State | New |
| Headers | show |
On 13/09/2016 16:49, Brijesh Singh wrote: > Fn8000_001f cpuid provides the memory encryption (aka C-bit) > > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> > --- > target-i386/cpu.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/target-i386/cpu.c b/target-i386/cpu.c > index 6a1afab..e039c08 100644 > --- a/target-i386/cpu.c > +++ b/target-i386/cpu.c > @@ -2625,6 +2625,9 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, > *edx = 0; > } > break; > + case 0x8000001F: > + host_cpuid(index, 0, eax, ebx, ecx, edx); > + break; > case 0xC0000000: > *eax = env->cpuid_xlevel2; > *ebx = 0; > > > This should only be visible to a SEV-enabled guest. Also, the xlevel should be bumped to 0x8000001F for SEV-enabled guests. Paolo
Hi Paolo, On 09/13/2016 06:07 PM, Paolo Bonzini wrote: > > > On 13/09/2016 16:49, Brijesh Singh wrote: >> Fn8000_001f cpuid provides the memory encryption (aka C-bit) >> >> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> >> --- >> target-i386/cpu.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/target-i386/cpu.c b/target-i386/cpu.c >> index 6a1afab..e039c08 100644 >> --- a/target-i386/cpu.c >> +++ b/target-i386/cpu.c >> @@ -2625,6 +2625,9 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, >> *edx = 0; >> } >> break; >> + case 0x8000001F: >> + host_cpuid(index, 0, eax, ebx, ecx, edx); >> + break; >> case 0xC0000000: >> *eax = env->cpuid_xlevel2; >> *ebx = 0; >> >> >> > > This should only be visible to a SEV-enabled guest. Also, the xlevel > should be bumped to 0x8000001F for SEV-enabled guests. > Okay I will add sev_enabled() check before getting the cpuid. Regarding xlevel, I am not able to locate qemu code which bumped the xelevel for KVM enabled guests. Maybe I am missing something, looking at code gave me impression that xlevel is obtained using CPUID_80000000. One of the KVM RFC patch [1] updates the min level. Do I need to do something more into qemu to bumped the xlevel? http://marc.info/?l=linux-mm&m=147190934724195&w=2 > Paolo >
On 21/09/2016 18:20, Brijesh Singh wrote: > Hi Paolo, > > On 09/13/2016 06:07 PM, Paolo Bonzini wrote: >> >> >> On 13/09/2016 16:49, Brijesh Singh wrote: >>> Fn8000_001f cpuid provides the memory encryption (aka C-bit) >>> >>> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> >>> --- >>> target-i386/cpu.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/target-i386/cpu.c b/target-i386/cpu.c >>> index 6a1afab..e039c08 100644 >>> --- a/target-i386/cpu.c >>> +++ b/target-i386/cpu.c >>> @@ -2625,6 +2625,9 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t >>> index, uint32_t count, >>> *edx = 0; >>> } >>> break; >>> + case 0x8000001F: >>> + host_cpuid(index, 0, eax, ebx, ecx, edx); >>> + break; >>> case 0xC0000000: >>> *eax = env->cpuid_xlevel2; >>> *ebx = 0; >>> >>> >>> >> >> This should only be visible to a SEV-enabled guest. Also, the xlevel >> should be bumped to 0x8000001F for SEV-enabled guests. >> > > Okay I will add sev_enabled() check before getting the cpuid. > > Regarding xlevel, I am not able to locate qemu code which bumped the > xelevel for KVM enabled guests. Maybe I am missing something, looking at > code gave me impression that xlevel is obtained using CPUID_80000000. > One of the KVM RFC patch [1] updates the min level. That patch makes sure that entry->eax is _at most_ 0x8000001f. Here you want to make sure that CPUID[0x80000000].EAX == 0x8000001f for SEV guests. I think you need to change x86_cpu_load_def: object_property_set_int(OBJECT(cpu), def->xlevel, "xlevel", errp); if SEV is enabled, use max(0x8000001f, def->xlevel) instead of def->xlevel. Paolo Do I need to do > something more into qemu to bumped the xlevel? > > http://marc.info/?l=linux-mm&m=147190934724195&w=2 > >> Paolo >>
On Wed, Sep 21, 2016 at 11:20:59AM -0500, Brijesh Singh wrote: > On 09/13/2016 06:07 PM, Paolo Bonzini wrote: > > On 13/09/2016 16:49, Brijesh Singh wrote: [...] > > > + case 0x8000001F: > > > + host_cpuid(index, 0, eax, ebx, ecx, edx); > > > + break; Do we really need to expose the raw host CPUID values directly to the guest? It will make it harder to support migration later. > > > case 0xC0000000: > > > *eax = env->cpuid_xlevel2; > > > *ebx = 0; > > > > > > > > > > > > > This should only be visible to a SEV-enabled guest. Also, the xlevel > > should be bumped to 0x8000001F for SEV-enabled guests. > > > > Okay I will add sev_enabled() check before getting the cpuid. > > Regarding xlevel, I am not able to locate qemu code which bumped the xelevel > for KVM enabled guests. Because QEMU doesn't do that automatically (yet), except for CPUID[7].EBX features. > Maybe I am missing something, looking at code gave > me impression that xlevel is obtained using CPUID_80000000. One of the KVM > RFC patch [1] updates the min level. Do I need to do something more into > qemu to bumped the xlevel? I will send a series today that will increase level/xlevel automatically depending on the features that are enabled. I will add you to CC.
diff --git a/target-i386/cpu.c b/target-i386/cpu.c index 6a1afab..e039c08 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -2625,6 +2625,9 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, *edx = 0; } break; + case 0x8000001F: + host_cpuid(index, 0, eax, ebx, ecx, edx); + break; case 0xC0000000: *eax = env->cpuid_xlevel2; *ebx = 0;
Fn8000_001f cpuid provides the memory encryption (aka C-bit) Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> --- target-i386/cpu.c | 3 +++ 1 file changed, 3 insertions(+)