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From: Jing Liu <jing2.liu@linux.intel.com>
To: pbonzini@redhat.com, seanjc@google.com
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2] KVM: x86: Revise guest_fpu xcomp_bv field
Date: Thu, 25 Feb 2021 05:49:54 -0500	[thread overview]
Message-ID: <20210225104955.3553-1-jing2.liu@linux.intel.com> (raw)

XCOMP_BV[63] field indicates that the save area is in the compacted
format and XCOMP_BV[62:0] indicates the states that have space allocated
in the save area, including both XCR0 and XSS bits enabled by the host
kernel. Use xfeatures_mask_all for calculating xcomp_bv and reuse
XCOMP_BV_COMPACTED_FORMAT defined by kernel.

Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>
---
 arch/x86/kvm/x86.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1b404e4d7dd8..f115493f577d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4435,8 +4435,6 @@ static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
-#define XSTATE_COMPACTION_ENABLED (1ULL << 63)
-
 static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu)
 {
 	struct xregs_state *xsave = &vcpu->arch.guest_fpu->state.xsave;
@@ -4494,7 +4492,8 @@ static void load_xsave(struct kvm_vcpu *vcpu, u8 *src)
 	/* Set XSTATE_BV and possibly XCOMP_BV.  */
 	xsave->header.xfeatures = xstate_bv;
 	if (boot_cpu_has(X86_FEATURE_XSAVES))
-		xsave->header.xcomp_bv = host_xcr0 | XSTATE_COMPACTION_ENABLED;
+		xsave->header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT |
+					 xfeatures_mask_all;
 
 	/*
 	 * Copy each region from the non-compacted offset to the
@@ -9912,9 +9911,6 @@ static void fx_init(struct kvm_vcpu *vcpu)
 		return;
 
 	fpstate_init(&vcpu->arch.guest_fpu->state);
-	if (boot_cpu_has(X86_FEATURE_XSAVES))
-		vcpu->arch.guest_fpu->state.xsave.header.xcomp_bv =
-			host_xcr0 | XSTATE_COMPACTION_ENABLED;
 
 	/*
 	 * Ensure guest xcr0 is valid for loading
-- 
2.18.4


             reply	other threads:[~2021-02-25  2:05 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-25 10:49 Jing Liu [this message]
2021-03-01 23:59 ` [PATCH v2] KVM: x86: Revise guest_fpu xcomp_bv field Sean Christopherson
2021-03-09  5:31   ` Liu, Jing2

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