linux-kernel - [PATCH 37/61] KVM: x86: Refactor handling of XSAVES CPUID adjustment

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Date:   Sat,  1 Feb 2020 10:51:54 -0800
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 37/61] KVM: x86: Refactor handling of XSAVES CPUID adjustment

Invert the handling of XSAVES, i.e. set it based on boot_cpu_has() by
default, in preparation for adding KVM cpu caps, which will generate the
mask at load time before ->xsaves_supported() is ready.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/cpuid.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index c74253202af8..20a7af320291 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -422,7 +422,6 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 	unsigned f_gbpages = 0;
 	unsigned f_lm = 0;
 #endif
-	unsigned f_xsaves = kvm_x86_ops->xsaves_supported() ? F(XSAVES) : 0;
 	unsigned f_intel_pt = kvm_x86_ops->pt_supported() ? F(INTEL_PT) : 0;
 
 	/* cpuid 1.edx */
@@ -479,7 +478,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 
 	/* cpuid 0xD.1.eax */
 	const u32 kvm_cpuid_D_1_eax_x86_features =
-		F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | f_xsaves;
+		F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | F(XSAVES);
 
 	/* all calls to cpuid_count() should be made on the same cpu */
 	get_cpu();
@@ -610,6 +609,10 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 
 		entry->eax &= kvm_cpuid_D_1_eax_x86_features;
 		cpuid_entry_mask(entry, CPUID_D_1_EAX);
+
+		if (!kvm_x86_ops->xsaves_supported())
+			cpuid_entry_clear(entry, X86_FEATURE_XSAVES);
+
 		if (entry->eax & (F(XSAVES)|F(XSAVEC)))
 			entry->ebx = xstate_required_size(supported_xcr0, true);
 		else
-- 
2.24.1