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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2020, Google LLC.
*
* Tests for KVM paravirtual feature disablement
*/
#include <asm/kvm_para.h>
#include <linux/kvm_para.h>
#include <stdint.h>
#include "test_util.h"
#include "kvm_util.h"
#include "processor.h"
struct msr_data {
uint32_t idx;
const char *name;
};
#define TEST_MSR(msr) { .idx = msr, .name = #msr }
#define UCALL_PR_MSR 0xdeadbeef
#define PR_MSR(msr) ucall(UCALL_PR_MSR, 1, msr)
/*
* KVM paravirtual msrs to test. Expect a #GP if any of these msrs are read or
* written, as the KVM_CPUID_FEATURES leaf is cleared.
*/
static struct msr_data msrs_to_test[] = {
TEST_MSR(MSR_KVM_SYSTEM_TIME),
TEST_MSR(MSR_KVM_SYSTEM_TIME_NEW),
TEST_MSR(MSR_KVM_WALL_CLOCK),
TEST_MSR(MSR_KVM_WALL_CLOCK_NEW),
TEST_MSR(MSR_KVM_ASYNC_PF_EN),
TEST_MSR(MSR_KVM_STEAL_TIME),
TEST_MSR(MSR_KVM_PV_EOI_EN),
TEST_MSR(MSR_KVM_POLL_CONTROL),
TEST_MSR(MSR_KVM_ASYNC_PF_INT),
TEST_MSR(MSR_KVM_ASYNC_PF_ACK),
};
static void test_msr(struct msr_data *msr)
{
uint64_t ignored;
uint8_t vector;
PR_MSR(msr);
vector = rdmsr_safe(msr->idx, &ignored);
GUEST_ASSERT_EQ(vector, GP_VECTOR);
vector = wrmsr_safe(msr->idx, 0);
GUEST_ASSERT_EQ(vector, GP_VECTOR);
}
struct hcall_data {
uint64_t nr;
const char *name;
};
#define TEST_HCALL(hc) { .nr = hc, .name = #hc }
#define UCALL_PR_HCALL 0xdeadc0de
#define PR_HCALL(hc) ucall(UCALL_PR_HCALL, 1, hc)
/*
* KVM hypercalls to test. Expect -KVM_ENOSYS when called, as the corresponding
* features have been cleared in KVM_CPUID_FEATURES.
*/
static struct hcall_data hcalls_to_test[] = {
TEST_HCALL(KVM_HC_KICK_CPU),
TEST_HCALL(KVM_HC_SEND_IPI),
TEST_HCALL(KVM_HC_SCHED_YIELD),
};
static void test_hcall(struct hcall_data *hc)
{
uint64_t r;
PR_HCALL(hc);
r = kvm_hypercall(hc->nr, 0, 0, 0, 0);
GUEST_ASSERT_EQ(r, -KVM_ENOSYS);
}
static void guest_main(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(msrs_to_test); i++) {
test_msr(&msrs_to_test[i]);
}
for (i = 0; i < ARRAY_SIZE(hcalls_to_test); i++) {
test_hcall(&hcalls_to_test[i]);
}
GUEST_DONE();
}
static void pr_msr(struct ucall *uc)
{
struct msr_data *msr = (struct msr_data *)uc->args[0];
pr_info("testing msr: %s (%#x)\n", msr->name, msr->idx);
}
static void pr_hcall(struct ucall *uc)
{
struct hcall_data *hc = (struct hcall_data *)uc->args[0];
pr_info("testing hcall: %s (%lu)\n", hc->name, hc->nr);
}
static void enter_guest(struct kvm_vcpu *vcpu)
{
struct ucall uc;
while (true) {
vcpu_run(vcpu);
TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
switch (get_ucall(vcpu, &uc)) {
case UCALL_PR_MSR:
pr_msr(&uc);
break;
case UCALL_PR_HCALL:
pr_hcall(&uc);
break;
case UCALL_ABORT:
REPORT_GUEST_ASSERT(uc);
return;
case UCALL_DONE:
return;
}
}
}
static void test_pv_unhalt(void)
{
struct kvm_vcpu *vcpu;
struct kvm_vm *vm;
struct kvm_cpuid_entry2 *ent;
u32 kvm_sig_old;
int r;
if (!(kvm_check_cap(KVM_CAP_X86_DISABLE_EXITS) & KVM_X86_DISABLE_EXITS_HLT))
return;
pr_info("testing KVM_FEATURE_PV_UNHALT\n");
/* KVM_PV_UNHALT test */
vm = vm_create_with_one_vcpu(&vcpu, guest_main);
vcpu_set_cpuid_feature(vcpu, X86_FEATURE_KVM_PV_UNHALT);
TEST_ASSERT(vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT),
"Enabling X86_FEATURE_KVM_PV_UNHALT had no effect");
/* Verify KVM disallows disabling exits after vCPU creation. */
r = __vm_enable_cap(vm, KVM_CAP_X86_DISABLE_EXITS, KVM_X86_DISABLE_EXITS_HLT);
TEST_ASSERT(r && errno == EINVAL,
"Disabling exits after vCPU creation didn't fail as expected");
kvm_vm_free(vm);
/* Verify that KVM clear PV_UNHALT from guest CPUID. */
vm = vm_create(1);
vm_enable_cap(vm, KVM_CAP_X86_DISABLE_EXITS, KVM_X86_DISABLE_EXITS_HLT);
vcpu = vm_vcpu_add(vm, 0, NULL);
TEST_ASSERT(!vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT),
"vCPU created with PV_UNHALT set by default");
vcpu_set_cpuid_feature(vcpu, X86_FEATURE_KVM_PV_UNHALT);
TEST_ASSERT(!vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT),
"PV_UNHALT set in guest CPUID when HLT-exiting is disabled");
/*
* Clobber the KVM PV signature and verify KVM does NOT clear PV_UNHALT
* when KVM PV is not present, and DOES clear PV_UNHALT when switching
* back to the correct signature..
*/
ent = vcpu_get_cpuid_entry(vcpu, KVM_CPUID_SIGNATURE);
kvm_sig_old = ent->ebx;
ent->ebx = 0xdeadbeef;
vcpu_set_cpuid(vcpu);
vcpu_set_cpuid_feature(vcpu, X86_FEATURE_KVM_PV_UNHALT);
TEST_ASSERT(vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT),
"PV_UNHALT cleared when using bogus KVM PV signature");
ent = vcpu_get_cpuid_entry(vcpu, KVM_CPUID_SIGNATURE);
ent->ebx = kvm_sig_old;
vcpu_set_cpuid(vcpu);
TEST_ASSERT(!vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT),
"PV_UNHALT set in guest CPUID when HLT-exiting is disabled");
/* FIXME: actually test KVM_FEATURE_PV_UNHALT feature */
kvm_vm_free(vm);
}
int main(void)
{
struct kvm_vcpu *vcpu;
struct kvm_vm *vm;
TEST_REQUIRE(kvm_has_cap(KVM_CAP_ENFORCE_PV_FEATURE_CPUID));
vm = vm_create_with_one_vcpu(&vcpu, guest_main);
vcpu_enable_cap(vcpu, KVM_CAP_ENFORCE_PV_FEATURE_CPUID, 1);
vcpu_clear_cpuid_entry(vcpu, KVM_CPUID_FEATURES);
enter_guest(vcpu);
kvm_vm_free(vm);
test_pv_unhalt();
}
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