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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"
extern unsigned char rdmsr_start;
extern unsigned char rdmsr_end;
static u64 do_rdmsr(u32 idx)
{
u32 lo, hi;
asm volatile("rdmsr_start: rdmsr;"
"rdmsr_end:"
: "=a"(lo), "=c"(hi)
: "c"(idx));
return (((u64) hi) << 32) | lo;
}
extern unsigned char wrmsr_start;
extern unsigned char wrmsr_end;
static void do_wrmsr(u32 idx, u64 val)
{
u32 lo, hi;
lo = val;
hi = val >> 32;
asm volatile("wrmsr_start: wrmsr;"
"wrmsr_end:"
: : "a"(lo), "c"(idx), "d"(hi));
}
static int nr_gp;
static void guest_gp_handler(struct ex_regs *regs)
{
unsigned char *rip = (unsigned char *)regs->rip;
bool r, w;
r = rip == &rdmsr_start;
w = rip == &wrmsr_start;
GUEST_ASSERT(r || w);
nr_gp++;
if (r)
regs->rip = (uint64_t)&rdmsr_end;
else
regs->rip = (uint64_t)&wrmsr_end;
}
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)
{
PR_MSR(msr);
do_rdmsr(msr->idx);
GUEST_ASSERT(READ_ONCE(nr_gp) == 1);
nr_gp = 0;
do_wrmsr(msr->idx, 0);
GUEST_ASSERT(READ_ONCE(nr_gp) == 1);
nr_gp = 0;
}
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(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 clear_kvm_cpuid_features(struct kvm_cpuid2 *cpuid)
{
struct kvm_cpuid_entry2 ent = {0};
ent.function = KVM_CPUID_FEATURES;
TEST_ASSERT(set_cpuid(cpuid, &ent),
"failed to clear KVM_CPUID_FEATURES leaf");
}
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 handle_abort(struct ucall *uc)
{
TEST_FAIL("%s at %s:%ld", (const char *)uc->args[0],
__FILE__, uc->args[1]);
}
#define VCPU_ID 0
static void enter_guest(struct kvm_vm *vm)
{
struct kvm_run *run;
struct ucall uc;
int r;
run = vcpu_state(vm, VCPU_ID);
while (true) {
r = _vcpu_run(vm, VCPU_ID);
TEST_ASSERT(!r, "vcpu_run failed: %d\n", r);
TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
"unexpected exit reason: %u (%s)",
run->exit_reason, exit_reason_str(run->exit_reason));
switch (get_ucall(vm, VCPU_ID, &uc)) {
case UCALL_PR_MSR:
pr_msr(&uc);
break;
case UCALL_PR_HCALL:
pr_hcall(&uc);
break;
case UCALL_ABORT:
handle_abort(&uc);
return;
case UCALL_DONE:
return;
}
}
}
int main(void)
{
struct kvm_enable_cap cap = {0};
struct kvm_cpuid2 *best;
struct kvm_vm *vm;
if (!kvm_check_cap(KVM_CAP_ENFORCE_PV_FEATURE_CPUID)) {
print_skip("KVM_CAP_ENFORCE_PV_FEATURE_CPUID not supported");
exit(KSFT_SKIP);
}
vm = vm_create_default(VCPU_ID, 0, guest_main);
cap.cap = KVM_CAP_ENFORCE_PV_FEATURE_CPUID;
cap.args[0] = 1;
vcpu_enable_cap(vm, VCPU_ID, &cap);
best = kvm_get_supported_cpuid();
clear_kvm_cpuid_features(best);
vcpu_set_cpuid(vm, VCPU_ID, best);
vm_init_descriptor_tables(vm);
vcpu_init_descriptor_tables(vm, VCPU_ID);
vm_install_exception_handler(vm, GP_VECTOR, guest_gp_handler);
enter_guest(vm);
kvm_vm_free(vm);
}
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