linux-kernel - [PATCH v3 7/8] KVM:X86: Add XSS bit 11 and 12 support for CET xsaves/xrstors.

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Date:   Mon, 25 Feb 2019 21:27:15 +0800
From:   Yang Weijiang <weijiang.yang@...el.com>
To:     pbonzini@...hat.com, rkrcmar@...hat.com,
        sean.j.christopherson@...el.com, jmattson@...gle.com,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org, mst@...hat.com,
        yu-cheng.yu@...el.com
Cc:     Yang Weijiang <weijiang.yang@...el.com>,
        Zhang Yi Z <yi.z.zhang@...ux.intel.com>
Subject: [PATCH v3 7/8] KVM:X86: Add XSS bit 11 and 12 support for CET xsaves/xrstors.

For Guest XSS, right now, only bit 11(user states) and bit 12
(supervisor states) are supported, if other bits are being set,
need to modify KVM_SUPPORTED_XSS macro to have support.

Signed-off-by: Zhang Yi Z <yi.z.zhang@...ux.intel.com>
Signed-off-by: Yang Weijiang <weijiang.yang@...el.com>
---
 arch/x86/kvm/vmx.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d32cee9ee079..68908ed7b151 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -47,6 +47,7 @@
 #include <asm/virtext.h>
 #include <asm/mce.h>
 #include <asm/fpu/internal.h>
+#include <asm/fpu/types.h>
 #include <asm/perf_event.h>
 #include <asm/debugreg.h>
 #include <asm/kexec.h>
@@ -4336,12 +4337,13 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	case MSR_IA32_XSS:
 		if (!vmx_xsaves_supported())
 			return 1;
+
 		/*
-		 * The only supported bit as of Skylake is bit 8, but
-		 * it is not supported on KVM.
+		 * Check bits being set are supported in KVM.
 		 */
-		if (data != 0)
+		if (data & ~kvm_supported_xss())
 			return 1;
+
 		vcpu->arch.ia32_xss = data;
 		if (vcpu->arch.ia32_xss != host_xss)
 			add_atomic_switch_msr(vmx, MSR_IA32_XSS,
-- 
2.17.1