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KVM: CPUID: add support for supervisor states

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Current CPUID 0xd enumeration code does not support supervisor
states, because KVM only supports setting IA32_XSS to zero.
Change it instead to use a new variable supported_xss, to be
set from the hardware_setup callback which is in charge of CPU
capabilities.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini
2020-03-05 16:11:56 +01:00
parent 257038745c
commit 408e9a318f
5 changed files with 31 additions and 16 deletions
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30
arch/x86/kvm/cpuid.c
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@@ -642,15 +642,22 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
cpuid_entry_override(entry, CPUID_D_1_EAX);
if (entry->eax & (F(XSAVES)|F(XSAVEC)))
entry->ebx = xstate_required_size(supported_xcr0, true);
else
entry->ebx = xstate_required_size(supported_xcr0 | supported_xss,
true);
else {
WARN_ON_ONCE(supported_xss != 0);
entry->ebx = 0;
/* Saving XSS controlled state via XSAVES isn't supported. */
entry->ecx = 0;
entry->edx = 0;
}
entry->ecx &= supported_xss;
entry->edx &= supported_xss >> 32;
for (i = 2; i < 64; ++i) {
if (!(supported_xcr0 & BIT_ULL(i)))
bool s_state;
if (supported_xcr0 & BIT_ULL(i))
s_state = false;
else if (supported_xss & BIT_ULL(i))
s_state = true;
else
continue;
entry = do_host_cpuid(array, function, i);
@@ -659,17 +666,16 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
/*
* The supported check above should have filtered out
* invalid sub-leafs as well as sub-leafs managed by
* IA32_XSS MSR. Only XCR0-managed sub-leafs should
* invalid sub-leafs. Only valid sub-leafs should
* reach this point, and they should have a non-zero
* save state size.
* save state size. Furthermore, check whether the
* processor agrees with supported_xcr0/supported_xss
* on whether this is an XCR0- or IA32_XSS-managed area.
*/
if (WARN_ON_ONCE(!entry->eax || (entry->ecx & 1))) {
if (WARN_ON_ONCE(!entry->eax || (entry->ecx & 0x1) != s_state)) {
--array->nent;
continue;
}
entry->ecx = 0;
entry->edx = 0;
}
break;