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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 <linux/stringify.h>
#include <stdint.h>
#include "apic.h"
#include "test_util.h"
#include "kvm_util.h"
#include "processor.h"
/* VMCALL and VMMCALL are both 3-byte opcodes. */
#define HYPERCALL_INSN_SIZE 3
static bool ud_expected;
static void guest_ud_handler(struct ex_regs *regs)
{
GUEST_ASSERT(ud_expected);
GUEST_DONE();
}
extern uint8_t svm_hypercall_insn[HYPERCALL_INSN_SIZE];
static uint64_t svm_do_sched_yield(uint8_t apic_id)
{
uint64_t ret;
asm volatile("mov %1, %%rax\n\t"
"mov %2, %%rbx\n\t"
"svm_hypercall_insn:\n\t"
"vmmcall\n\t"
"mov %%rax, %0\n\t"
: "=r"(ret)
: "r"((uint64_t)KVM_HC_SCHED_YIELD), "r"((uint64_t)apic_id)
: "rax", "rbx", "memory");
return ret;
}
extern uint8_t vmx_hypercall_insn[HYPERCALL_INSN_SIZE];
static uint64_t vmx_do_sched_yield(uint8_t apic_id)
{
uint64_t ret;
asm volatile("mov %1, %%rax\n\t"
"mov %2, %%rbx\n\t"
"vmx_hypercall_insn:\n\t"
"vmcall\n\t"
"mov %%rax, %0\n\t"
: "=r"(ret)
: "r"((uint64_t)KVM_HC_SCHED_YIELD), "r"((uint64_t)apic_id)
: "rax", "rbx", "memory");
return ret;
}
static void guest_main(void)
{
uint8_t *native_hypercall_insn, *hypercall_insn;
uint8_t apic_id;
apic_id = GET_APIC_ID_FIELD(xapic_read_reg(APIC_ID));
if (is_intel_cpu()) {
native_hypercall_insn = vmx_hypercall_insn;
hypercall_insn = svm_hypercall_insn;
svm_do_sched_yield(apic_id);
} else if (is_amd_cpu()) {
native_hypercall_insn = svm_hypercall_insn;
hypercall_insn = vmx_hypercall_insn;
vmx_do_sched_yield(apic_id);
} else {
GUEST_ASSERT(0);
/* unreachable */
return;
}
/*
* The hypercall didn't #UD (guest_ud_handler() signals "done" if a #UD
* occurs). Verify that a #UD is NOT expected and that KVM patched in
* the native hypercall.
*/
GUEST_ASSERT(!ud_expected);
GUEST_ASSERT(!memcmp(native_hypercall_insn, hypercall_insn, HYPERCALL_INSN_SIZE));
GUEST_DONE();
}
static void setup_ud_vector(struct kvm_vcpu *vcpu)
{
vm_init_descriptor_tables(vcpu->vm);
vcpu_init_descriptor_tables(vcpu);
vm_install_exception_handler(vcpu->vm, UD_VECTOR, guest_ud_handler);
}
static void enter_guest(struct kvm_vcpu *vcpu)
{
struct kvm_run *run = vcpu->run;
struct ucall uc;
vcpu_run(vcpu);
switch (get_ucall(vcpu, &uc)) {
case UCALL_SYNC:
pr_info("%s: %016lx\n", (const char *)uc.args[2], uc.args[3]);
break;
case UCALL_DONE:
return;
case UCALL_ABORT:
REPORT_GUEST_ASSERT(uc);
default:
TEST_FAIL("Unhandled ucall: %ld\nexit_reason: %u (%s)",
uc.cmd, run->exit_reason, exit_reason_str(run->exit_reason));
}
}
static void test_fix_hypercall(void)
{
struct kvm_vcpu *vcpu;
struct kvm_vm *vm;
vm = vm_create_with_one_vcpu(&vcpu, guest_main);
setup_ud_vector(vcpu);
ud_expected = false;
sync_global_to_guest(vm, ud_expected);
virt_pg_map(vm, APIC_DEFAULT_GPA, APIC_DEFAULT_GPA);
enter_guest(vcpu);
}
static void test_fix_hypercall_disabled(void)
{
struct kvm_vcpu *vcpu;
struct kvm_vm *vm;
vm = vm_create_with_one_vcpu(&vcpu, guest_main);
setup_ud_vector(vcpu);
vm_enable_cap(vm, KVM_CAP_DISABLE_QUIRKS2,
KVM_X86_QUIRK_FIX_HYPERCALL_INSN);
ud_expected = true;
sync_global_to_guest(vm, ud_expected);
virt_pg_map(vm, APIC_DEFAULT_GPA, APIC_DEFAULT_GPA);
enter_guest(vcpu);
}
int main(void)
{
TEST_REQUIRE(kvm_check_cap(KVM_CAP_DISABLE_QUIRKS2) & KVM_X86_QUIRK_FIX_HYPERCALL_INSN);
test_fix_hypercall();
test_fix_hypercall_disabled();
}
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