1 files changed, 36 insertions, 36 deletions

diff --git a/tools/testing/selftests/kvm/lib/x86_64/ucall.c b/tools/testing/selftests/kvm/lib/x86_64/ucall.c
index da4d89ad5419..1265cecc7dd1 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/ucall.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/ucall.c
@@ -8,49 +8,49 @@
 
 #define UCALL_PIO_PORT ((uint16_t)0x1000)
 
-void ucall_init(struct kvm_vm *vm, void *arg)
+void ucall_arch_do_ucall(vm_vaddr_t uc)
 {
+	/*
+	 * FIXME: Revert this hack (the entire commit that added it) once nVMX
+	 * preserves L2 GPRs across a nested VM-Exit.  If a ucall from L2, e.g.
+	 * to do a GUEST_SYNC(), lands the vCPU in L1, any and all GPRs can be
+	 * clobbered by L1.  Save and restore non-volatile GPRs (clobbering RBP
+	 * in particular is problematic) along with RDX and RDI (which are
+	 * inputs), and clobber volatile GPRs. *sigh*
+	 */
+#define HORRIFIC_L2_UCALL_CLOBBER_HACK	\
+	"rcx", "rsi", "r8", "r9", "r10", "r11"
+
+	asm volatile("push %%rbp\n\t"
+		     "push %%r15\n\t"
+		     "push %%r14\n\t"
+		     "push %%r13\n\t"
+		     "push %%r12\n\t"
+		     "push %%rbx\n\t"
+		     "push %%rdx\n\t"
+		     "push %%rdi\n\t"
+		     "in %[port], %%al\n\t"
+		     "pop %%rdi\n\t"
+		     "pop %%rdx\n\t"
+		     "pop %%rbx\n\t"
+		     "pop %%r12\n\t"
+		     "pop %%r13\n\t"
+		     "pop %%r14\n\t"
+		     "pop %%r15\n\t"
+		     "pop %%rbp\n\t"
+		: : [port] "d" (UCALL_PIO_PORT), "D" (uc) : "rax", "memory",
+		     HORRIFIC_L2_UCALL_CLOBBER_HACK);
 }
 
-void ucall_uninit(struct kvm_vm *vm)
+void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
 {
-}
-
-void ucall(uint64_t cmd, int nargs, ...)
-{
-	struct ucall uc = {
-		.cmd = cmd,
-	};
-	va_list va;
-	int i;
-
-	nargs = nargs <= UCALL_MAX_ARGS ? nargs : UCALL_MAX_ARGS;
-
-	va_start(va, nargs);
-	for (i = 0; i < nargs; ++i)
-		uc.args[i] = va_arg(va, uint64_t);
-	va_end(va);
-
-	asm volatile("in %[port], %%al"
-		: : [port] "d" (UCALL_PIO_PORT), "D" (&uc) : "rax", "memory");
-}
-
-uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc)
-{
-	struct kvm_run *run = vcpu_state(vm, vcpu_id);
-	struct ucall ucall = {};
+	struct kvm_run *run = vcpu->run;
 
 	if (run->exit_reason == KVM_EXIT_IO && run->io.port == UCALL_PIO_PORT) {
 		struct kvm_regs regs;
 
-		vcpu_regs_get(vm, vcpu_id, &regs);
-		memcpy(&ucall, addr_gva2hva(vm, (vm_vaddr_t)regs.rdi),
-		       sizeof(ucall));
-
-		vcpu_run_complete_io(vm, vcpu_id);
-		if (uc)
-			memcpy(uc, &ucall, sizeof(ucall));
+		vcpu_regs_get(vcpu, &regs);
+		return (void *)regs.rdi;
 	}
-
-	return ucall.cmd;
+	return NULL;
 }