[PATCH 3/8] KVM: selftests: Reuse GPR switching logic for nVMX

[Yosry Ahmed <yosry@kernel.org>]

From: Yosry Ahmed <yosryahmed@google.com>

Reuse the GPR switching logic for nVMX by adding a wrapper that also
switches RAX, replacing the push/pop of a subset of the registers.

Signed-off-by: Yosry Ahmed <yosry@kernel.org>
---
 .../selftests/kvm/include/x86/processor.h     |  5 ++
 tools/testing/selftests/kvm/include/x86/vmx.h | 46 +++++--------------
 2 files changed, 17 insertions(+), 34 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h
index 8e4eab84b91bc..ca2ec92490f7c 100644
--- a/tools/testing/selftests/kvm/include/x86/processor.h
+++ b/tools/testing/selftests/kvm/include/x86/processor.h
@@ -402,6 +402,7 @@ extern struct gpr64_regs guest_regs;
 #define DEFINE_ASM_GPR64_OFFSET(reg) \
 	asm(".equ GPR64_OFF_" #reg ", %c0" : : "i"(offsetof(struct gpr64_regs, reg)))
 
+DEFINE_ASM_GPR64_OFFSET(rax);
 DEFINE_ASM_GPR64_OFFSET(rbx);
 DEFINE_ASM_GPR64_OFFSET(rcx);
 DEFINE_ASM_GPR64_OFFSET(rdx);
@@ -439,6 +440,10 @@ DEFINE_ASM_GPR64_OFFSET(r15);
 	GUEST_SWITCH_GPR_ASM(r14) \
 	GUEST_SWITCH_GPR_ASM(r15)
 
+#define GUEST_SWITCH_GPRS_ASM \
+	GUEST_SWITCH_GPR_ASM(rax) \
+	GUEST_SWITCH_GPRS_NORAX_ASM
+
 struct desc64 {
 	u16 limit0;
 	u16 base0;
diff --git a/tools/testing/selftests/kvm/include/x86/vmx.h b/tools/testing/selftests/kvm/include/x86/vmx.h
index 90fffaf915958..a7f6f0c9b6b9d 100644
--- a/tools/testing/selftests/kvm/include/x86/vmx.h
+++ b/tools/testing/selftests/kvm/include/x86/vmx.h
@@ -363,9 +363,6 @@ static inline u64 vmptrstz(void)
 	return value;
 }
 
-/*
- * No guest state (e.g. GPRs) is established by this vmlaunch.
- */
 static inline int vmlaunch(void)
 {
 	int ret;
@@ -373,34 +370,23 @@ static inline int vmlaunch(void)
 	if (enable_evmcs)
 		return evmcs_vmlaunch();
 
-	__asm__ __volatile__("push %%rbp;"
-			     "push %%rcx;"
-			     "push %%rdx;"
-			     "push %%rsi;"
-			     "push %%rdi;"
-			     "push $0;"
+	__asm__ __volatile__("push $0;"
 			     "vmwrite %%rsp, %[host_rsp];"
 			     "lea 1f(%%rip), %%rax;"
 			     "vmwrite %%rax, %[host_rip];"
+			     GUEST_SWITCH_GPRS_ASM
 			     "vmlaunch;"
 			     "incq (%%rsp);"
-			     "1: pop %%rax;"
-			     "pop %%rdi;"
-			     "pop %%rsi;"
-			     "pop %%rdx;"
-			     "pop %%rcx;"
-			     "pop %%rbp;"
+			     "1: ;"
+			     GUEST_SWITCH_GPRS_ASM
+			     "pop %%rax;"
 			     : [ret]"=&a"(ret)
 			     : [host_rsp]"r"((u64)HOST_RSP),
 			       [host_rip]"r"((u64)HOST_RIP)
-			     : "memory", "cc", "rbx", "r8", "r9", "r10",
-			       "r11", "r12", "r13", "r14", "r15");
+			     : "memory", "cc");
 	return ret;
 }
 
-/*
- * No guest state (e.g. GPRs) is established by this vmresume.
- */
 static inline int vmresume(void)
 {
 	int ret;
@@ -408,28 +394,20 @@ static inline int vmresume(void)
 	if (enable_evmcs)
 		return evmcs_vmresume();
 
-	__asm__ __volatile__("push %%rbp;"
-			     "push %%rcx;"
-			     "push %%rdx;"
-			     "push %%rsi;"
-			     "push %%rdi;"
-			     "push $0;"
+	__asm__ __volatile__("push $0;"
 			     "vmwrite %%rsp, %[host_rsp];"
 			     "lea 1f(%%rip), %%rax;"
 			     "vmwrite %%rax, %[host_rip];"
+			     GUEST_SWITCH_GPRS_ASM
 			     "vmresume;"
 			     "incq (%%rsp);"
-			     "1: pop %%rax;"
-			     "pop %%rdi;"
-			     "pop %%rsi;"
-			     "pop %%rdx;"
-			     "pop %%rcx;"
-			     "pop %%rbp;"
+			     "1: ;"
+			     GUEST_SWITCH_GPRS_ASM
+			     "pop %%rax;"
 			     : [ret]"=&a"(ret)
 			     : [host_rsp]"r"((u64)HOST_RSP),
 			       [host_rip]"r"((u64)HOST_RIP)
-			     : "memory", "cc", "rbx", "r8", "r9", "r10",
-			       "r11", "r12", "r13", "r14", "r15");
+			     : "memory", "cc");
 	return ret;
 }
 
-- 
2.54.0.563.g4f69b47b94-goog