// SPDX-License-Identifier: GPL-2.0
/*
* KVM dirty page logging test
*
* Copyright (C) 2018, Red Hat, Inc.
*/
#include <stdio.h>
#include <stdlib.h>
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include "test_util.h"
#include "kvm_util.h"
#include "processor.h"
#include "vmx.h"
/* The memory slot index to track dirty pages */
#define TEST_MEM_SLOT_INDEX 1
#define TEST_MEM_PAGES 3
/* L1 guest test virtual memory offset */
#define GUEST_TEST_MEM 0xc0000000
/* L2 guest test virtual memory offset */
#define NESTED_TEST_MEM1 0xc0001000
#define NESTED_TEST_MEM2 0xc0002000
static void l2_guest_code(u64 *a, u64 *b)
{
READ_ONCE(*a);
WRITE_ONCE(*a, 1);
GUEST_SYNC(true);
GUEST_SYNC(false);
WRITE_ONCE(*b, 1);
GUEST_SYNC(true);
WRITE_ONCE(*b, 1);
GUEST_SYNC(true);
GUEST_SYNC(false);
/* Exit to L1 and never come back. */
vmcall();
}
static void l2_guest_code_ept_enabled(void)
{
l2_guest_code((u64 *)NESTED_TEST_MEM1, (u64 *)NESTED_TEST_MEM2);
}
static void l2_guest_code_ept_disabled(void)
{
/* Access the same L1 GPAs as l2_guest_code_ept_enabled() */
l2_guest_code((u64 *)GUEST_TEST_MEM, (u64 *)GUEST_TEST_MEM);
}
void l1_guest_code(struct vmx_pages *vmx)
{
#define L2_GUEST_STACK_SIZE 64
unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
void *l2_rip;
GUEST_ASSERT(vmx->vmcs_gpa);
GUEST_ASSERT(prepare_for_vmx_operation(vmx));
GUEST_ASSERT(load_vmcs(vmx));
if (vmx->eptp_gpa)
l2_rip = l2_guest_code_ept_enabled;
else
l2_rip = l2_guest_code_ept_disabled;
prepare_vmcs(vmx, l2_rip, &l2_guest_stack[L2_GUEST_STACK_SIZE]);
GUEST_SYNC(false);
GUEST_ASSERT(!vmlaunch());
GUEST_SYNC(false);
GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
GUEST_DONE();
}
static void test_vmx_dirty_log(bool enable_ept)
{
vm_vaddr_t vmx_pages_gva = 0;
struct vmx_pages *vmx;
unsigned long *bmap;
uint64_t *host_test_mem;
struct kvm_vcpu *vcpu;
struct kvm_vm *vm;
struct ucall uc;
bool done = false;
pr_info("Nested EPT: %s\n", enable_ept ? "enabled" : "disabled");
/* Create VM */
vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code);
vmx = vcpu_alloc_vmx(vm, &vmx_pages_gva);
vcpu_args_set(vcpu, 1, vmx_pages_gva);
/* Add an extra memory slot for testing dirty logging */
vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
GUEST_TEST_MEM,
TEST_MEM_SLOT_INDEX,
TEST_MEM_PAGES,
KVM_MEM_LOG_DIRTY_PAGES);
/*
* Add an identity map for GVA range [0xc0000000, 0xc0002000). This
* affects both L1 and L2. However...
*/
virt_map(vm, GUEST_TEST_MEM, GUEST_TEST_MEM, TEST_MEM_PAGES);
/*
* ... pages in the L2 GPA range [0xc0001000, 0xc0003000) will map to
* 0xc0000000.
*
* Note that prepare_eptp should be called only L1's GPA map is done,
* meaning after the last call to virt_map.
*
* When EPT is disabled, the L2 guest code will still access the same L1
* GPAs as the EPT enabled case.
*/
if (enable_ept) {
prepare_eptp(vmx, vm, 0);
nested_map_memslot(vmx, vm, 0);
nested_map(vmx, vm, NESTED_TEST_MEM1, GUEST_TEST_MEM, 4096);
nested_map(vmx, vm, NESTED_TEST_MEM2, GUEST_TEST_MEM, 4096);
}
bmap = bitmap_zalloc(TEST_MEM_PAGES);
host_test_mem = addr_gpa2hva(vm, GUEST_TEST_MEM);
while (!done) {
memset(host_test_mem, 0xaa, TEST_MEM_PAGES * 4096);
vcpu_run(vcpu);
TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
switch (get_ucall(vcpu, &uc)) {
case UCALL_ABORT:
REPORT_GUEST_ASSERT(uc);
/* NOT REACHED */
case UCALL_SYNC:
/*
* The nested guest wrote at offset 0x1000 in the memslot, but the
* dirty bitmap must be filled in according to L1 GPA, not L2.
*/
kvm_vm_get_dirty_log(vm, TEST_MEM_SLOT_INDEX, bmap);
if (uc.args[1]) {
TEST_ASSERT(test_bit(0, bmap), "Page 0 incorrectly reported clean");
TEST_ASSERT(host_test_mem[0] == 1, "Page 0 not written by guest");
} else {
TEST_ASSERT(!test_bit(0, bmap), "Page 0 incorrectly reported dirty");
TEST_ASSERT(host_test_mem[0] == 0xaaaaaaaaaaaaaaaaULL, "Page 0 written by guest");
}
TEST_ASSERT(!test_bit(1, bmap), "Page 1 incorrectly reported dirty");
TEST_ASSERT(host_test_mem[4096 / 8] == 0xaaaaaaaaaaaaaaaaULL, "Page 1 written by guest");
TEST_ASSERT(!test_bit(2, bmap), "Page 2 incorrectly reported dirty");
TEST_ASSERT(host_test_mem[8192 / 8] == 0xaaaaaaaaaaaaaaaaULL, "Page 2 written by guest");
break;
case UCALL_DONE:
done = true;
break;
default:
TEST_FAIL("Unknown ucall %lu", uc.cmd);
}
}
}
int main(int argc, char *argv[])
{
TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));
test_vmx_dirty_log(/*enable_ept=*/false);
if (kvm_cpu_has_ept())
test_vmx_dirty_log(/*enable_ept=*/true);
return 0;
}
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