Commit 408e9a31 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: CPUID: add support for supervisor states 



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: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 25703874

arch/x86/kvm/cpuid.c

+18 −12
Original line number Diff line number Diff line
@@ -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;

arch/x86/kvm/svm.c

+2 −0
Original line number Diff line number Diff line
@@ -1371,6 +1371,8 @@ static __init void svm_set_cpu_caps(void) 
{

	kvm_set_cpu_caps();



	supported_xss = 0;



	/* CPUID 0x80000001 and 0x8000000A (SVM features) */

	if (nested) {

		kvm_cpu_cap_set(X86_FEATURE_SVM);

arch/x86/kvm/vmx/vmx.c

+1 −0
Original line number Diff line number Diff line
@@ -7126,6 +7126,7 @@ static __init void vmx_set_cpu_caps(void) 
		kvm_cpu_cap_set(X86_FEATURE_UMIP);



	/* CPUID 0xD.1 */

	supported_xss = 0;

	if (!vmx_xsaves_supported())

		kvm_cpu_cap_clear(X86_FEATURE_XSAVES);

arch/x86/kvm/x86.c

+9 −4
Original line number Diff line number Diff line
@@ -190,6 +190,8 @@ u64 __read_mostly host_efer; 
EXPORT_SYMBOL_GPL(host_efer);



static u64 __read_mostly host_xss;

u64 __read_mostly supported_xss;

EXPORT_SYMBOL_GPL(supported_xss);



struct kvm_stats_debugfs_item debugfs_entries[] = {

	{ "pf_fixed", VCPU_STAT(pf_fixed) },
@@ -2827,7 +2829,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) 
		 * IA32_XSS[bit 8]. Guests have to use RDMSR/WRMSR rather than

		 * XSAVES/XRSTORS to save/restore PT MSRs.

		 */

		if (data != 0)

		if (data & ~supported_xss)

			return 1;

		vcpu->arch.ia32_xss = data;

		break;
@@ -9617,10 +9619,16 @@ int kvm_arch_hardware_setup(void) 


	rdmsrl_safe(MSR_EFER, &host_efer);



	if (boot_cpu_has(X86_FEATURE_XSAVES))

		rdmsrl(MSR_IA32_XSS, host_xss);



	r = kvm_x86_ops->hardware_setup();

	if (r != 0)

		return r;



	if (!kvm_cpu_cap_has(X86_FEATURE_XSAVES))

		supported_xss = 0;



	cr4_reserved_bits = kvm_host_cr4_reserved_bits(&boot_cpu_data);



	if (kvm_has_tsc_control) {
@@ -9637,9 +9645,6 @@ int kvm_arch_hardware_setup(void) 
		kvm_default_tsc_scaling_ratio = 1ULL << kvm_tsc_scaling_ratio_frac_bits;

	}



	if (boot_cpu_has(X86_FEATURE_XSAVES))

		rdmsrl(MSR_IA32_XSS, host_xss);



	kvm_init_msr_list();

	return 0;

}

arch/x86/kvm/x86.h

+1 −0
Original line number Diff line number Diff line
@@ -272,6 +272,7 @@ enum exit_fastpath_completion handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vc 


extern u64 host_xcr0;

extern u64 supported_xcr0;

extern u64 supported_xss;



static inline bool kvm_mpx_supported(void)

{