[PATCH 1/3] KVM: selftests: Add support for per-VM ucall ops on x86

[Sean Christopherson]

Add a layer of indirection to x86's ucall infrastructure to allow wiring up
a different set of {do,get}_ucall() operations for TDX VMs.  TDX can't use
port I/O (at least, not robustly), as the TDX ABI doesn't allow the guest
to share arbitrary register state with the host on a PIO exit, and the PIO
data payload is limited to 4 bytes, i.e. would potentially truncate the
address of the per-ucall structure.

No functional change intended, as the ops are still hardwirte to the common
x86 ucall functions.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 .../testing/selftests/kvm/include/x86/ucall.h |  6 +----
 tools/testing/selftests/kvm/lib/x86/ucall.c   | 27 +++++++++++++++++--
 2 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86/ucall.h b/tools/testing/selftests/kvm/include/x86/ucall.h
index 0e4950041e3e..3639f03a4da9 100644
--- a/tools/testing/selftests/kvm/include/x86/ucall.h
+++ b/tools/testing/selftests/kvm/include/x86/ucall.h
@@ -2,12 +2,8 @@
 #ifndef SELFTEST_KVM_UCALL_H
 #define SELFTEST_KVM_UCALL_H
 
-#include "kvm_util.h"
+#include "linux/kvm.h"
 
 #define UCALL_EXIT_REASON       KVM_EXIT_IO
 
-static inline void ucall_arch_init(struct kvm_vm *vm, gpa_t mmio_gpa)
-{
-}
-
 #endif
diff --git a/tools/testing/selftests/kvm/lib/x86/ucall.c b/tools/testing/selftests/kvm/lib/x86/ucall.c
index e7dd5791959b..444d0f0ba138 100644
--- a/tools/testing/selftests/kvm/lib/x86/ucall.c
+++ b/tools/testing/selftests/kvm/lib/x86/ucall.c
@@ -8,7 +8,7 @@
 
 #define UCALL_PIO_PORT ((u16)0x1000)
 
-void ucall_arch_do_ucall(gva_t uc)
+static void ucall_x86_do_ucall(gva_t uc)
 {
 	/*
 	 * FIXME: Revert this hack (the entire commit that added it) once nVMX
@@ -42,7 +42,7 @@ void ucall_arch_do_ucall(gva_t uc)
 		     HORRIFIC_L2_UCALL_CLOBBER_HACK);
 }
 
-void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
+static void *ucall_x86_get_ucall(struct kvm_vcpu *vcpu)
 {
 	struct kvm_run *run = vcpu->run;
 
@@ -54,3 +54,26 @@ void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
 	}
 	return NULL;
 }
+
+static struct {
+	void (*do_ucall)(gva_t uc);
+	void *(*get_ucall)(struct kvm_vcpu *vcpu);
+} ucall_x86_ops = {
+	.do_ucall = ucall_x86_do_ucall,
+	.get_ucall = ucall_x86_get_ucall,
+};
+
+void ucall_arch_init(struct kvm_vm *vm, gpa_t mmio_gpa)
+{
+	sync_global_to_guest(vm, ucall_x86_ops);
+}
+
+void ucall_arch_do_ucall(gva_t uc)
+{
+	return ucall_x86_ops.do_ucall(uc);
+}
+
+void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
+{
+	return ucall_x86_ops.get_ucall(vcpu);
+}

base-commit: 8ab7454faa8be2d6c1fc29c857b9f9611ddb174b
-- 
2.55.0.897.gb25b4bd76c-goog


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