[RFC,59/67] KVM: VMX: Move AR_BYTES encoder/decoder helpers to common.h

Commit Message

Isaku Yamahata Nov. 16, 2020, 6:26 p.m. UTC

From: Sean Christopherson <[e-mail]>

Move the AR_BYTES helpers to common.h so that future patches can reuse
them to decode/encode AR for TDX.

Signed-off-by: Sean Christopherson <[e-mail]>
---
 arch/x86/kvm/vmx/common.h | 41 ++++++++++++++++++++++++++++++++++
 arch/x86/kvm/vmx/vmx.c    | 46 ++++-----------------------------------
 2 files changed, 45 insertions(+), 42 deletions(-)

Patch

diff --git a/arch/x86/kvm/vmx/common.h b/arch/x86/kvm/vmx/common.h
index baee96abdd7e..ad106364c51f 100644
--- a/arch/x86/kvm/vmx/common.h
+++ b/arch/x86/kvm/vmx/common.h
@@ -4,6 +4,7 @@ 
 
 #include <linux/kvm_host.h>
 
+#include <asm/kvm.h>
 #include <asm/traps.h>
 #include <asm/vmx.h>
 
@@ -121,4 +122,44 @@  static inline int __vmx_handle_ept_violation(struct kvm_vcpu *vcpu, gpa_t gpa,
 	return kvm_mmu_page_fault(vcpu, gpa, error_code, NULL, 0);
 }
 
+static inline u32 vmx_encode_ar_bytes(struct kvm_segment *var)
+{
+	u32 ar;
+
+	if (var->unusable || !var->present)
+		ar = 1 << 16;
+	else {
+		ar = var->type & 15;
+		ar |= (var->s & 1) << 4;
+		ar |= (var->dpl & 3) << 5;
+		ar |= (var->present & 1) << 7;
+		ar |= (var->avl & 1) << 12;
+		ar |= (var->l & 1) << 13;
+		ar |= (var->db & 1) << 14;
+		ar |= (var->g & 1) << 15;
+	}
+
+	return ar;
+}
+
+static inline void vmx_decode_ar_bytes(u32 ar, struct kvm_segment *var)
+{
+	var->unusable = (ar >> 16) & 1;
+	var->type = ar & 15;
+	var->s = (ar >> 4) & 1;
+	var->dpl = (ar >> 5) & 3;
+	/*
+	 * Some userspaces do not preserve unusable property. Since usable
+	 * segment has to be present according to VMX spec we can use present
+	 * property to amend userspace bug by making unusable segment always
+	 * nonpresent. vmx_encode_ar_bytes() already marks nonpresent
+	 * segment as unusable.
+	 */
+	var->present = !var->unusable;
+	var->avl = (ar >> 12) & 1;
+	var->l = (ar >> 13) & 1;
+	var->db = (ar >> 14) & 1;
+	var->g = (ar >> 15) & 1;
+}
+
 #endif /* __KVM_X86_VMX_COMMON_H */
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 85401a7eef9a..8bd71b91c6f0 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -361,7 +361,6 @@  static const struct kernel_param_ops vmentry_l1d_flush_ops = {
 };
 module_param_cb(vmentry_l1d_flush, &vmentry_l1d_flush_ops, NULL, 0644);
 
-static u32 vmx_segment_access_rights(struct kvm_segment *var);
 static __always_inline void vmx_disable_intercept_for_msr(struct kvm_vcpu *vcpu,
 							  u32 msr, int type);
 
@@ -2736,7 +2735,7 @@  static void fix_rmode_seg(int seg, struct kvm_segment *save)
 	vmcs_write16(sf->selector, var.selector);
 	vmcs_writel(sf->base, var.base);
 	vmcs_write32(sf->limit, var.limit);
-	vmcs_write32(sf->ar_bytes, vmx_segment_access_rights(&var));
+	vmcs_write32(sf->ar_bytes, vmx_encode_ar_bytes(&var));
 }
 
 static void enter_rmode(struct kvm_vcpu *vcpu)
@@ -3131,7 +3130,6 @@  int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
 void vmx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	u32 ar;
 
 	if (vmx->rmode.vm86_active && seg != VCPU_SREG_LDTR) {
 		*var = vmx->rmode.segs[seg];
@@ -3145,23 +3143,7 @@  void vmx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg)
 	var->base = vmx_read_guest_seg_base(vmx, seg);
 	var->limit = vmx_read_guest_seg_limit(vmx, seg);
 	var->selector = vmx_read_guest_seg_selector(vmx, seg);
-	ar = vmx_read_guest_seg_ar(vmx, seg);
-	var->unusable = (ar >> 16) & 1;
-	var->type = ar & 15;
-	var->s = (ar >> 4) & 1;
-	var->dpl = (ar >> 5) & 3;
-	/*
-	 * Some userspaces do not preserve unusable property. Since usable
-	 * segment has to be present according to VMX spec we can use present
-	 * property to amend userspace bug by making unusable segment always
-	 * nonpresent. vmx_segment_access_rights() already marks nonpresent
-	 * segment as unusable.
-	 */
-	var->present = !var->unusable;
-	var->avl = (ar >> 12) & 1;
-	var->l = (ar >> 13) & 1;
-	var->db = (ar >> 14) & 1;
-	var->g = (ar >> 15) & 1;
+	vmx_decode_ar_bytes(vmx_read_guest_seg_ar(vmx, seg), var);
 }
 
 static u64 vmx_get_segment_base(struct kvm_vcpu *vcpu, int seg)
@@ -3187,26 +3169,6 @@  int vmx_get_cpl(struct kvm_vcpu *vcpu)
 	}
 }
 
-static u32 vmx_segment_access_rights(struct kvm_segment *var)
-{
-	u32 ar;
-
-	if (var->unusable || !var->present)
-		ar = 1 << 16;
-	else {
-		ar = var->type & 15;
-		ar |= (var->s & 1) << 4;
-		ar |= (var->dpl & 3) << 5;
-		ar |= (var->present & 1) << 7;
-		ar |= (var->avl & 1) << 12;
-		ar |= (var->l & 1) << 13;
-		ar |= (var->db & 1) << 14;
-		ar |= (var->g & 1) << 15;
-	}
-
-	return ar;
-}
-
 void vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -3241,7 +3203,7 @@  void vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg)
 	if (is_unrestricted_guest(vcpu) && (seg != VCPU_SREG_LDTR))
 		var->type |= 0x1; /* Accessed */
 
-	vmcs_write32(sf->ar_bytes, vmx_segment_access_rights(var));
+	vmcs_write32(sf->ar_bytes, vmx_encode_ar_bytes(var));
 
 out:
 	vmx->emulation_required = emulation_required(vcpu);
@@ -3288,7 +3250,7 @@  static bool rmode_segment_valid(struct kvm_vcpu *vcpu, int seg)
 	var.dpl = 0x3;
 	if (seg == VCPU_SREG_CS)
 		var.type = 0x3;
-	ar = vmx_segment_access_rights(&var);
+	ar = vmx_encode_ar_bytes(&var);
 
 	if (var.base != (var.selector << 4))
 		return false;