linux-kernel - [PATCH kvm-unit-tests 1/2] svm: Add ability to execute test via test

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Date:   Mon,  8 Jun 2020 08:27:59 -0400
From:   Cathy Avery <cavery@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        pbonzini@...hat.com
Subject: [PATCH kvm-unit-tests 1/2] svm: Add ability to execute test via test_run on a vcpu other than vcpu 0

When running tests that can result in a vcpu being left in an
indeterminate state it is useful to be able to run the test on
a vcpu other than 0. This patch allows test_run to be executed
on any vcpu indicated by the on_vcpu member of the svm_test struct.
The initialized state of the vcpu0 registers used to populate the
vmcb is carried forward to the other vcpus.

Signed-off-by: Cathy Avery <cavery@...hat.com>
---
 x86/svm.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
 x86/svm.h | 13 +++++++++++++
 2 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/x86/svm.c b/x86/svm.c
index 41685bf..9f7ae7e 100644
--- a/x86/svm.c
+++ b/x86/svm.c
@@ -367,6 +367,45 @@ test_wanted(const char *name, char *filters[], int filter_count)
         }
 }
 
+static void set_additional_vpcu_regs(struct extra_vcpu_info *info)
+{
+    wrmsr(MSR_VM_HSAVE_PA, info->hsave);
+    wrmsr(MSR_EFER, rdmsr(MSR_EFER) | EFER_SVME);
+    wrmsr(MSR_EFER, rdmsr(MSR_EFER) | EFER_NX);
+    write_cr3(info->cr3);
+    write_cr4(info->cr4);
+    write_cr0(info->cr0);
+    write_dr6(info->dr6);
+    write_dr7(info->dr7);
+    write_cr2(info->cr2);
+    wrmsr(MSR_IA32_CR_PAT, info->g_pat);
+    wrmsr(MSR_IA32_DEBUGCTLMSR, info->dbgctl);
+}
+
+static void get_additional_vcpu_regs(struct extra_vcpu_info *info)
+{
+    info->hsave = rdmsr(MSR_VM_HSAVE_PA);
+    info->cr3 = read_cr3();
+    info->cr4 = read_cr4();
+    info->cr0 = read_cr0();
+    info->dr7 = read_dr7();
+    info->dr6 = read_dr6();
+    info->cr2 = read_cr2();
+    info->g_pat = rdmsr(MSR_IA32_CR_PAT);
+    info->dbgctl = rdmsr(MSR_IA32_DEBUGCTLMSR);
+}
+
+static void init_additional_vcpu_regs(void)
+{
+    int i;
+    struct extra_vcpu_info info;
+
+    get_additional_vcpu_regs(&info);
+
+    for (i = 1; i < cpu_count(); i++)
+        on_cpu(i, (void *)set_additional_vpcu_regs, &info);
+}
+
 int main(int ac, char **av)
 {
 	int i = 0;
@@ -384,6 +423,8 @@ int main(int ac, char **av)
 
 	setup_svm();
 
+        init_additional_vcpu_regs();
+
 	vmcb = alloc_page();
 
 	for (; svm_tests[i].name != NULL; i++) {
@@ -392,7 +433,13 @@ int main(int ac, char **av)
 		if (svm_tests[i].supported && !svm_tests[i].supported())
 			continue;
 		if (svm_tests[i].v2 == NULL) {
-			test_run(&svm_tests[i]);
+			if (svm_tests[i].on_vcpu) {
+				if (cpu_count() <= svm_tests[i].on_vcpu)
+					continue;
+				on_cpu(svm_tests[i].on_vcpu, (void *)test_run, &svm_tests[i]);
+			}
+			else
+				test_run(&svm_tests[i]);
 		} else {
 			vmcb_ident(vmcb);
 			v2_test = &(svm_tests[i]);
diff --git a/x86/svm.h b/x86/svm.h
index 645deb7..d023a32 100644
--- a/x86/svm.h
+++ b/x86/svm.h
@@ -338,6 +338,7 @@ struct svm_test {
 	ulong scratch;
 	/* Alternative test interface. */
 	void (*v2)(void);
+	int on_vcpu;
 };
 
 struct regs {
@@ -360,6 +361,18 @@ struct regs {
 	u64 rflags;
 };
 
+struct extra_vcpu_info {
+	u64 hsave;
+	u64 cr3;
+	u64 cr4;
+	u64 cr0;
+	u64 dr7;
+	u64 dr6;
+	u64 cr2;
+	u64 g_pat;
+	u64 dbgctl;
+};
+
 typedef void (*test_guest_func)(struct svm_test *);
 
 u64 *npt_get_pte(u64 address);
-- 
2.20.1