KVM: arm64: selftests: Add tests for MMIO external abort injection

Test that the plumbing exposed to userspace for injecting aborts in
response to unexpected MMIO works as intended in two different flavors:

 - A 'normal' MMIO instruction (i.e. ESR_ELx.ISV=1)

 - An ISV=0 MMIO instruction with/without KVM_CAP_ARM_NISV_TO_USER
   enabled

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241025203106.3529261-5-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Oliver Upton
2024-10-25 20:31:06 +00:00
parent c660d334b3
commit 3eb09a3e02
2 changed files with 160 additions and 0 deletions

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@@ -156,6 +156,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/aarch32_id_regs
TEST_GEN_PROGS_aarch64 += aarch64/arch_timer_edge_cases
TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions
TEST_GEN_PROGS_aarch64 += aarch64/hypercalls
TEST_GEN_PROGS_aarch64 += aarch64/mmio_abort
TEST_GEN_PROGS_aarch64 += aarch64/page_fault_test
TEST_GEN_PROGS_aarch64 += aarch64/psci_test
TEST_GEN_PROGS_aarch64 += aarch64/set_id_regs

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@@ -0,0 +1,159 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* mmio_abort - Tests for userspace MMIO abort injection
*
* Copyright (c) 2024 Google LLC
*/
#include "processor.h"
#include "test_util.h"
#define MMIO_ADDR 0x8000000ULL
static u64 expected_abort_pc;
static void expect_sea_handler(struct ex_regs *regs)
{
u64 esr = read_sysreg(esr_el1);
GUEST_ASSERT_EQ(regs->pc, expected_abort_pc);
GUEST_ASSERT_EQ(ESR_ELx_EC(esr), ESR_ELx_EC_DABT_CUR);
GUEST_ASSERT_EQ(esr & ESR_ELx_FSC_TYPE, ESR_ELx_FSC_EXTABT);
GUEST_DONE();
}
static void unexpected_dabt_handler(struct ex_regs *regs)
{
GUEST_FAIL("Unexpected data abort at PC: %lx\n", regs->pc);
}
static struct kvm_vm *vm_create_with_dabt_handler(struct kvm_vcpu **vcpu, void *guest_code,
handler_fn dabt_handler)
{
struct kvm_vm *vm = vm_create_with_one_vcpu(vcpu, guest_code);
vm_init_descriptor_tables(vm);
vcpu_init_descriptor_tables(*vcpu);
vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT, ESR_ELx_EC_DABT_CUR, dabt_handler);
virt_map(vm, MMIO_ADDR, MMIO_ADDR, 1);
return vm;
}
static void vcpu_inject_extabt(struct kvm_vcpu *vcpu)
{
struct kvm_vcpu_events events = {};
events.exception.ext_dabt_pending = true;
vcpu_events_set(vcpu, &events);
}
static void vcpu_run_expect_done(struct kvm_vcpu *vcpu)
{
struct ucall uc;
vcpu_run(vcpu);
switch (get_ucall(vcpu, &uc)) {
case UCALL_ABORT:
REPORT_GUEST_ASSERT(uc);
break;
case UCALL_DONE:
break;
default:
TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
}
}
extern char test_mmio_abort_insn;
static void test_mmio_abort_guest(void)
{
WRITE_ONCE(expected_abort_pc, (u64)&test_mmio_abort_insn);
asm volatile("test_mmio_abort_insn:\n\t"
"ldr x0, [%0]\n\t"
: : "r" (MMIO_ADDR) : "x0", "memory");
GUEST_FAIL("MMIO instruction should not retire");
}
/*
* Test that KVM doesn't complete MMIO emulation when userspace has made an
* external abort pending for the instruction.
*/
static void test_mmio_abort(void)
{
struct kvm_vcpu *vcpu;
struct kvm_vm *vm = vm_create_with_dabt_handler(&vcpu, test_mmio_abort_guest,
expect_sea_handler);
struct kvm_run *run = vcpu->run;
vcpu_run(vcpu);
TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_MMIO);
TEST_ASSERT_EQ(run->mmio.phys_addr, MMIO_ADDR);
TEST_ASSERT_EQ(run->mmio.len, sizeof(unsigned long));
TEST_ASSERT(!run->mmio.is_write, "Expected MMIO read");
vcpu_inject_extabt(vcpu);
vcpu_run_expect_done(vcpu);
kvm_vm_free(vm);
}
extern char test_mmio_nisv_insn;
static void test_mmio_nisv_guest(void)
{
WRITE_ONCE(expected_abort_pc, (u64)&test_mmio_nisv_insn);
asm volatile("test_mmio_nisv_insn:\n\t"
"ldr x0, [%0], #8\n\t"
: : "r" (MMIO_ADDR) : "x0", "memory");
GUEST_FAIL("MMIO instruction should not retire");
}
/*
* Test that the KVM_RUN ioctl fails for ESR_EL2.ISV=0 MMIO aborts if userspace
* hasn't enabled KVM_CAP_ARM_NISV_TO_USER.
*/
static void test_mmio_nisv(void)
{
struct kvm_vcpu *vcpu;
struct kvm_vm *vm = vm_create_with_dabt_handler(&vcpu, test_mmio_nisv_guest,
unexpected_dabt_handler);
TEST_ASSERT(_vcpu_run(vcpu), "Expected nonzero return code from KVM_RUN");
TEST_ASSERT_EQ(errno, ENOSYS);
kvm_vm_free(vm);
}
/*
* Test that ESR_EL2.ISV=0 MMIO aborts reach userspace and that an injected SEA
* reaches the guest.
*/
static void test_mmio_nisv_abort(void)
{
struct kvm_vcpu *vcpu;
struct kvm_vm *vm = vm_create_with_dabt_handler(&vcpu, test_mmio_nisv_guest,
expect_sea_handler);
struct kvm_run *run = vcpu->run;
vm_enable_cap(vm, KVM_CAP_ARM_NISV_TO_USER, 1);
vcpu_run(vcpu);
TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_ARM_NISV);
TEST_ASSERT_EQ(run->arm_nisv.fault_ipa, MMIO_ADDR);
vcpu_inject_extabt(vcpu);
vcpu_run_expect_done(vcpu);
kvm_vm_free(vm);
}
int main(void)
{
test_mmio_abort();
test_mmio_nisv();
test_mmio_nisv_abort();
}