[PATCH v2 2/2] kvm: vmx: enable intel xsaves for guest

[Wanpeng Li]

Expose intel xsaves feature to guest.

Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
---
v1 -> v2:
 *auto switch msr ia32_xss if this msr is present

 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/include/asm/vmx.h      |  3 +++
 arch/x86/include/uapi/asm/vmx.h |  6 +++++-
 arch/x86/kvm/vmx.c              | 35 ++++++++++++++++++++++++++++++++++-
 4 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 2896dbc..95dde42 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -362,6 +362,7 @@ struct kvm_vcpu_arch {
 	int mp_state;
 	u64 ia32_misc_enable_msr;
 	bool tpr_access_reporting;
+	u64 ia32_xss;
 
 	/*
 	 * Paging state of the vcpu
diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index bcbfade..bdb79ef 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -69,6 +69,7 @@
 #define SECONDARY_EXEC_PAUSE_LOOP_EXITING	0x00000400
 #define SECONDARY_EXEC_ENABLE_INVPCID		0x00001000
 #define SECONDARY_EXEC_SHADOW_VMCS              0x00004000
+#define SECONDARY_EXEC_XSAVES			0x00100000
 
 
 #define PIN_BASED_EXT_INTR_MASK                 0x00000001
@@ -159,6 +160,8 @@ enum vmcs_field {
 	EOI_EXIT_BITMAP3_HIGH           = 0x00002023,
 	VMREAD_BITMAP                   = 0x00002026,
 	VMWRITE_BITMAP                  = 0x00002028,
+	XSS_EXIT_BIMTAP                 = 0x0000202C,
+	XSS_EXIT_BIMTAP_HIGH            = 0x0000202D,
 	GUEST_PHYSICAL_ADDRESS          = 0x00002400,
 	GUEST_PHYSICAL_ADDRESS_HIGH     = 0x00002401,
 	VMCS_LINK_POINTER               = 0x00002800,
diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h
index 990a2fe..b813bf9 100644
--- a/arch/x86/include/uapi/asm/vmx.h
+++ b/arch/x86/include/uapi/asm/vmx.h
@@ -72,6 +72,8 @@
 #define EXIT_REASON_XSETBV              55
 #define EXIT_REASON_APIC_WRITE          56
 #define EXIT_REASON_INVPCID             58
+#define EXIT_REASON_XSAVES              63
+#define EXIT_REASON_XRSTORS             64
 
 #define VMX_EXIT_REASONS \
 	{ EXIT_REASON_EXCEPTION_NMI,         "EXCEPTION_NMI" }, \
@@ -116,6 +118,8 @@
 	{ EXIT_REASON_INVALID_STATE,         "INVALID_STATE" }, \
 	{ EXIT_REASON_INVD,                  "INVD" }, \
 	{ EXIT_REASON_INVVPID,               "INVVPID" }, \
-	{ EXIT_REASON_INVPCID,               "INVPCID" }
+	{ EXIT_REASON_INVPCID,               "INVPCID" }, \
+	{ EXIT_REASON_XSAVES,                "XSAVES" }, \
+	{ EXIT_REASON_XRSTORS,               "XRSTORS" }
 
 #endif /* _UAPIVMX_H */
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6a951d8..b87b5b8 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1045,6 +1045,12 @@ static inline bool cpu_has_vmx_invpcid(void)
 		SECONDARY_EXEC_ENABLE_INVPCID;
 }
 
+static inline bool cpu_has_xss_exit_bitmap(void)
+{
+	return vmcs_config.cpu_based_2nd_exec_ctrl &
+		SECONDARY_EXEC_XSAVES;
+}
+
 static inline bool cpu_has_virtual_nmis(void)
 {
 	return vmcs_config.pin_based_exec_ctrl & PIN_BASED_VIRTUAL_NMIS;
@@ -1773,6 +1779,14 @@ static void vmx_save_host_state(struct kvm_vcpu *vcpu)
 		kvm_set_shared_msr(vmx->guest_msrs[i].index,
 				   vmx->guest_msrs[i].data,
 				   vmx->guest_msrs[i].mask);
+
+	if (cpu_has_xsaves) {
+		u64 host_xss;
+
+		rdmsrl(MSR_IA32_XSS, host_xss);
+		add_atomic_switch_msr(vmx, MSR_IA32_XSS,
+				vcpu->arch.ia32_xss, host_xss);
+	}
 }
 
 static void __vmx_load_host_state(struct vcpu_vmx *vmx)
@@ -2895,7 +2909,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
 			SECONDARY_EXEC_ENABLE_INVPCID |
 			SECONDARY_EXEC_APIC_REGISTER_VIRT |
 			SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
-			SECONDARY_EXEC_SHADOW_VMCS;
+			SECONDARY_EXEC_SHADOW_VMCS |
+			SECONDARY_EXEC_XSAVES;
 		if (adjust_vmx_controls(min2, opt2,
 					MSR_IA32_VMX_PROCBASED_CTLS2,
 					&_cpu_based_2nd_exec_control) < 0)
@@ -4346,6 +4361,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
 	unsigned long a;
 #endif
 	int i;
+	u64 xss = 0;
 
 	/* I/O */
 	vmcs_write64(IO_BITMAP_A, __pa(vmx_io_bitmap_a));
@@ -4446,6 +4462,9 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
 	vmcs_writel(CR0_GUEST_HOST_MASK, ~0UL);
 	set_cr4_guest_host_mask(vmx);
 
+	if (cpu_has_xss_exit_bitmap())
+		vmcs_write64(XSS_EXIT_BIMTAP, xss);
+
 	return 0;
 }
 
@@ -5334,6 +5353,18 @@ static int handle_xsetbv(struct kvm_vcpu *vcpu)
 	return 1;
 }
 
+static int handle_xsaves(struct kvm_vcpu *vcpu)
+{
+	skip_emulated_instruction(vcpu);
+	return 1;
+}
+
+static int handle_xrstors(struct kvm_vcpu *vcpu)
+{
+	skip_emulated_instruction(vcpu);
+	return 1;
+}
+
 static int handle_apic_access(struct kvm_vcpu *vcpu)
 {
 	if (likely(fasteoi)) {
@@ -6951,6 +6982,8 @@ static int (*const kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
 	[EXIT_REASON_MONITOR_INSTRUCTION]     = handle_monitor,
 	[EXIT_REASON_INVEPT]                  = handle_invept,
 	[EXIT_REASON_INVVPID]                 = handle_invvpid,
+	[EXIT_REASON_XSAVES]                  = handle_xsaves,
+	[EXIT_REASON_XRSTORS]                 = handle_xrstors,
 };
 
 static const int kvm_vmx_max_exit_handlers =
-- 
1.9.1

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