[PATCH v4 18/21] KVM: selftests: Extend vmx_dirty_log_test to cover SVM

Sean Christopherson
2025-12-30T23:02:26Z

From: Yosry Ahmed <yosry.ahmed@linux.dev>

Generalize the code in vmx_dirty_log_test.c by adding SVM-specific L1
code, doing some renaming (e.g. EPT -> TDP), and having setup code for
both SVM and VMX in test_dirty_log().

Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
tools/testing/selftests/kvm/Makefile.kvm | 2 +-
...rty_log_test.c => nested_dirty_log_test.c} | 73 ++++++++++++++-----
2 files changed, 54 insertions(+), 21 deletions(-)
rename tools/testing/selftests/kvm/x86/{vmx_dirty_log_test.c => nested_dirty_log_test.c} (71%)

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index ba5c2b643efa..8f14213ddef1 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -89,6 +89,7 @@ TEST_GEN_PROGS_x86 += x86/kvm_buslock_test
TEST_GEN_PROGS_x86 += x86/monitor_mwait_test
TEST_GEN_PROGS_x86 += x86/msrs_test
TEST_GEN_PROGS_x86 += x86/nested_close_kvm_test
+TEST_GEN_PROGS_x86 += x86/nested_dirty_log_test
TEST_GEN_PROGS_x86 += x86/nested_emulation_test
TEST_GEN_PROGS_x86 += x86/nested_exceptions_test
TEST_GEN_PROGS_x86 += x86/nested_invalid_cr3_test
@@ -115,7 +116,6 @@ TEST_GEN_PROGS_x86 += x86/ucna_injection_test
TEST_GEN_PROGS_x86 += x86/userspace_io_test
TEST_GEN_PROGS_x86 += x86/userspace_msr_exit_test
TEST_GEN_PROGS_x86 += x86/vmx_apic_access_test
-TEST_GEN_PROGS_x86 += x86/vmx_dirty_log_test
TEST_GEN_PROGS_x86 += x86/vmx_exception_with_invalid_guest_state
TEST_GEN_PROGS_x86 += x86/vmx_msrs_test
TEST_GEN_PROGS_x86 += x86/vmx_invalid_nested_guest_state
diff --git a/tools/testing/selftests/kvm/x86/vmx_dirty_log_test.c b/tools/testing/selftests/kvm/x86/nested_dirty_log_test.c
similarity index 71%
rename from tools/testing/selftests/kvm/x86/vmx_dirty_log_test.c
rename to tools/testing/selftests/kvm/x86/nested_dirty_log_test.c
index 032ab8bf60a4..89d2e86a0db9 100644
--- a/tools/testing/selftests/kvm/x86/vmx_dirty_log_test.c
+++ b/tools/testing/selftests/kvm/x86/nested_dirty_log_test.c
@@ -12,6 +12,7 @@
#include "test_util.h"
#include "kvm_util.h"
#include "processor.h"
+#include "svm_util.h"
#include "vmx.h"

/* The memory slot index to track dirty pages */
@@ -25,6 +26,8 @@
#define NESTED_TEST_MEM1 0xc0001000
#define NESTED_TEST_MEM2 0xc0002000

+#define L2_GUEST_STACK_SIZE 64
+
static void l2_guest_code(u64 *a, u64 *b)
{
READ_ONCE(*a);
@@ -42,20 +45,19 @@ static void l2_guest_code(u64 *a, u64 *b)
vmcall();
}

-static void l2_guest_code_ept_enabled(void)
+static void l2_guest_code_tdp_enabled(void)
{
l2_guest_code((u64 *)NESTED_TEST_MEM1, (u64 *)NESTED_TEST_MEM2);
}

-static void l2_guest_code_ept_disabled(void)
+static void l2_guest_code_tdp_disabled(void)
{
- /* Access the same L1 GPAs as l2_guest_code_ept_enabled() */
+ /* Access the same L1 GPAs as l2_guest_code_tdp_enabled() */
l2_guest_code((u64 *)GUEST_TEST_MEM, (u64 *)GUEST_TEST_MEM);
}

-void l1_guest_code(struct vmx_pages *vmx)
+void l1_vmx_code(struct vmx_pages *vmx)
{
-#define L2_GUEST_STACK_SIZE 64
unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
void *l2_rip;

@@ -64,22 +66,49 @@ void l1_guest_code(struct vmx_pages *vmx)
GUEST_ASSERT(load_vmcs(vmx));

if (vmx->eptp_gpa)
- l2_rip = l2_guest_code_ept_enabled;
+ l2_rip = l2_guest_code_tdp_enabled;
else
- l2_rip = l2_guest_code_ept_disabled;
+ l2_rip = l2_guest_code_tdp_disabled;

prepare_vmcs(vmx, l2_rip, &l2_guest_stack[L2_GUEST_STACK_SIZE]);

GUEST_SYNC(false);
GUEST_ASSERT(!vmlaunch());
GUEST_SYNC(false);
- GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
+ GUEST_ASSERT_EQ(vmreadz(VM_EXIT_REASON), EXIT_REASON_VMCALL);
GUEST_DONE();
}

-static void test_vmx_dirty_log(bool enable_ept)
+static void l1_svm_code(struct svm_test_data *svm)
{
- vm_vaddr_t vmx_pages_gva = 0;
+ unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
+ void *l2_rip;
+
+ if (svm->ncr3_gpa)
+ l2_rip = l2_guest_code_tdp_enabled;
+ else
+ l2_rip = l2_guest_code_tdp_disabled;
+
+ generic_svm_setup(svm, l2_rip, &l2_guest_stack[L2_GUEST_STACK_SIZE]);
+
+ GUEST_SYNC(false);
+ run_guest(svm->vmcb, svm->vmcb_gpa);
+ GUEST_SYNC(false);
+ GUEST_ASSERT_EQ(svm->vmcb->control.exit_code, SVM_EXIT_VMMCALL);
+ GUEST_DONE();
+}
+
+static void l1_guest_code(void *data)
+{
+ if (this_cpu_has(X86_FEATURE_VMX))
+ l1_vmx_code(data);
+ else
+ l1_svm_code(data);
+}
+
+static void test_dirty_log(bool nested_tdp)
+{
+ vm_vaddr_t nested_gva = 0;
unsigned long *bmap;
uint64_t *host_test_mem;

@@ -88,15 +117,19 @@ static void test_vmx_dirty_log(bool enable_ept)
struct ucall uc;
bool done = false;

- pr_info("Nested EPT: %s\n", enable_ept ? "enabled" : "disabled");
+ pr_info("Nested TDP: %s\n", nested_tdp ? "enabled" : "disabled");

/* Create VM */
vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code);
- if (enable_ept)
+ if (nested_tdp)
vm_enable_tdp(vm);

- vcpu_alloc_vmx(vm, &vmx_pages_gva);
- vcpu_args_set(vcpu, 1, vmx_pages_gva);
+ if (kvm_cpu_has(X86_FEATURE_VMX))
+ vcpu_alloc_vmx(vm, &nested_gva);
+ else
+ vcpu_alloc_svm(vm, &nested_gva);
+
+ vcpu_args_set(vcpu, 1, nested_gva);

/* Add an extra memory slot for testing dirty logging */
vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
@@ -115,10 +148,10 @@ static void test_vmx_dirty_log(bool enable_ept)
* ... pages in the L2 GPA range [0xc0001000, 0xc0003000) will map to
* 0xc0000000.
*
- * When EPT is disabled, the L2 guest code will still access the same L1
- * GPAs as the EPT enabled case.
+ * When TDP is disabled, the L2 guest code will still access the same L1
+ * GPAs as the TDP enabled case.
*/
- if (enable_ept) {
+ if (nested_tdp) {
tdp_identity_map_default_memslots(vm);
tdp_map(vm, NESTED_TEST_MEM1, GUEST_TEST_MEM, PAGE_SIZE);
tdp_map(vm, NESTED_TEST_MEM2, GUEST_TEST_MEM, PAGE_SIZE);
@@ -166,12 +199,12 @@ static void test_vmx_dirty_log(bool enable_ept)

int main(int argc, char *argv[])
{
- TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));
+ TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX) || kvm_cpu_has(X86_FEATURE_SVM));

- test_vmx_dirty_log(/*enable_ept=*/false);
+ test_dirty_log(/*nested_tdp=*/false);

if (kvm_cpu_has_tdp())
- test_vmx_dirty_log(/*enable_ept=*/true);
+ test_dirty_log(/*nested_tdp=*/true);

return 0;
}
--
2.52.0.351.gbe84eed79e-goog