[PATCH v7 1/8] KVM: x86: Provide INVLPG linear address to intercept handlers

[Tina Zhang]

INVLPG's memory operand is decoded with NoAccess, and thus src_val does
not contain the operand address.  Intercept handlers therefore cannot
construct exit state that reports the linear address from the existing
x86_instruction_info fields.

Add get_invlpg_linear_addr() to compute the address through __linearize(),
using the same flags as em_invlpg(), and pass the result through
x86_instruction_info.

Signed-off-by: Tina Zhang <zhang_wei@xxxxxxxxxxxxxx>
---
 arch/x86/kvm/emulate.c     | 23 +++++++++++++++++++++++
 arch/x86/kvm/kvm_emulate.h |  1 +
 2 files changed, 24 insertions(+)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c1b21282187f..2972a35b0ac0 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -411,6 +411,9 @@ static int em_salc(struct x86_emulate_ctxt *ctxt)
 	_fault ? X86EMUL_UNHANDLEABLE : X86EMUL_CONTINUE; \
 })
 
+static u64 get_invlpg_linear_addr(struct x86_emulate_ctxt *ctxt,
+				  enum x86_intercept intercept);
+
 static int emulator_check_intercept(struct x86_emulate_ctxt *ctxt,
 				    enum x86_intercept intercept,
 				    enum x86_intercept_stage stage)
@@ -428,6 +431,7 @@ static int emulator_check_intercept(struct x86_emulate_ctxt *ctxt,
 		.src_type   = ctxt->src.type,
 		.dst_type   = ctxt->dst.type,
 		.ad_bytes   = ctxt->ad_bytes,
+		.invlpg_linear_addr = get_invlpg_linear_addr(ctxt, intercept),
 		.rip	    = ctxt->eip,
 		.next_rip   = ctxt->_eip,
 	};
@@ -684,6 +688,25 @@ static __always_inline int __linearize(struct x86_emulate_ctxt *ctxt,
 		return emulate_gp(ctxt, 0);
 }
 
+static u64 get_invlpg_linear_addr(struct x86_emulate_ctxt *ctxt,
+				  enum x86_intercept intercept)
+{
+	unsigned int max_size;
+	unsigned long linear = 0;
+
+	if (intercept != x86_intercept_invlpg)
+		return 0;
+
+	/*
+	 * Use the same address calculation as em_invlpg() for the address
+	 * reported to L1.  Ignore address-check failures, as __linearize()
+	 * sets linear before reporting a failure.
+	 */
+	__linearize(ctxt, ctxt->src.addr.mem, &max_size, 1, ctxt->mode,
+		    &linear, X86EMUL_F_INVLPG);
+	return linear;
+}
+
 static int linearize(struct x86_emulate_ctxt *ctxt,
 		     struct segmented_address addr,
 		     unsigned size, bool write,
diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h
index 3e375af15c03..d05558ef28ae 100644
--- a/arch/x86/kvm/kvm_emulate.h
+++ b/arch/x86/kvm/kvm_emulate.h
@@ -51,6 +51,7 @@ struct x86_instruction_info {
 	u8  src_type;		/* type of source operand		*/
 	u8  dst_type;		/* type of destination operand		*/
 	u8  ad_bytes;           /* size of src/dst address              */
+	u64 invlpg_linear_addr;	/* linear address, if INVLPG */
 	u64 rip;		/* rip of the instruction		*/
 	u64 next_rip;           /* rip following the instruction        */
 };
-- 
2.43.7