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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Test TEST PROTECTION emulation.
*
* Copyright IBM Corp. 2021
*/
#include <sys/mman.h>
#include "test_util.h"
#include "kvm_util.h"
#define PAGE_SHIFT 12
#define PAGE_SIZE (1 << PAGE_SHIFT)
#define CR0_FETCH_PROTECTION_OVERRIDE (1UL << (63 - 38))
#define CR0_STORAGE_PROTECTION_OVERRIDE (1UL << (63 - 39))
#define VCPU_ID 1
static __aligned(PAGE_SIZE) uint8_t pages[2][PAGE_SIZE];
static uint8_t *const page_store_prot = pages[0];
static uint8_t *const page_fetch_prot = pages[1];
/* Nonzero return value indicates that address not mapped */
static int set_storage_key(void *addr, uint8_t key)
{
int not_mapped = 0;
asm volatile (
"lra %[addr], 0(0,%[addr])\n"
" jz 0f\n"
" llill %[not_mapped],1\n"
" j 1f\n"
"0: sske %[key], %[addr]\n"
"1:"
: [addr] "+&a" (addr), [not_mapped] "+r" (not_mapped)
: [key] "r" (key)
: "cc"
);
return -not_mapped;
}
enum permission {
READ_WRITE = 0,
READ = 1,
RW_PROTECTED = 2,
TRANSL_UNAVAIL = 3,
};
static enum permission test_protection(void *addr, uint8_t key)
{
uint64_t mask;
asm volatile (
"tprot %[addr], 0(%[key])\n"
" ipm %[mask]\n"
: [mask] "=r" (mask)
: [addr] "Q" (*(char *)addr),
[key] "a" (key)
: "cc"
);
return (enum permission)(mask >> 28);
}
enum stage {
STAGE_END,
STAGE_INIT_SIMPLE,
TEST_SIMPLE,
STAGE_INIT_FETCH_PROT_OVERRIDE,
TEST_FETCH_PROT_OVERRIDE,
TEST_STORAGE_PROT_OVERRIDE,
};
struct test {
enum stage stage;
void *addr;
uint8_t key;
enum permission expected;
} tests[] = {
/*
* We perform each test in the array by executing TEST PROTECTION on
* the specified addr with the specified key and checking if the returned
* permissions match the expected value.
* Both guest and host cooperate to set up the required test conditions.
* A central condition is that the page targeted by addr has to be DAT
* protected in the host mappings, in order for KVM to emulate the
* TEST PROTECTION instruction.
* Since the page tables are shared, the host uses mprotect to achieve
* this.
*
* Test resulting in RW_PROTECTED/TRANSL_UNAVAIL will be interpreted
* by SIE, not KVM, but there is no harm in testing them also.
* See Enhanced Suppression-on-Protection Facilities in the
* Interpretive-Execution Mode
*/
/*
* guest: set storage key of page_store_prot to 1
* storage key of page_fetch_prot to 9 and enable
* protection for it
* STAGE_INIT_SIMPLE
* host: write protect both via mprotect
*/
/* access key 0 matches any storage key -> RW */
{ TEST_SIMPLE, page_store_prot, 0x00, READ_WRITE },
/* access key matches storage key -> RW */
{ TEST_SIMPLE, page_store_prot, 0x10, READ_WRITE },
/* mismatched keys, but no fetch protection -> RO */
{ TEST_SIMPLE, page_store_prot, 0x20, READ },
/* access key 0 matches any storage key -> RW */
{ TEST_SIMPLE, page_fetch_prot, 0x00, READ_WRITE },
/* access key matches storage key -> RW */
{ TEST_SIMPLE, page_fetch_prot, 0x90, READ_WRITE },
/* mismatched keys, fetch protection -> inaccessible */
{ TEST_SIMPLE, page_fetch_prot, 0x10, RW_PROTECTED },
/* page 0 not mapped yet -> translation not available */
{ TEST_SIMPLE, (void *)0x00, 0x10, TRANSL_UNAVAIL },
/*
* host: try to map page 0
* guest: set storage key of page 0 to 9 and enable fetch protection
* STAGE_INIT_FETCH_PROT_OVERRIDE
* host: write protect page 0
* enable fetch protection override
*/
/* mismatched keys, fetch protection, but override applies -> RO */
{ TEST_FETCH_PROT_OVERRIDE, (void *)0x00, 0x10, READ },
/* mismatched keys, fetch protection, override applies to 0-2048 only -> inaccessible */
{ TEST_FETCH_PROT_OVERRIDE, (void *)2049, 0x10, RW_PROTECTED },
/*
* host: enable storage protection override
*/
/* mismatched keys, but override applies (storage key 9) -> RW */
{ TEST_STORAGE_PROT_OVERRIDE, page_fetch_prot, 0x10, READ_WRITE },
/* mismatched keys, no fetch protection, override doesn't apply -> RO */
{ TEST_STORAGE_PROT_OVERRIDE, page_store_prot, 0x20, READ },
/* mismatched keys, but override applies (storage key 9) -> RW */
{ TEST_STORAGE_PROT_OVERRIDE, (void *)2049, 0x10, READ_WRITE },
/* end marker */
{ STAGE_END, 0, 0, 0 },
};
static enum stage perform_next_stage(int *i, bool mapped_0)
{
enum stage stage = tests[*i].stage;
enum permission result;
bool skip;
for (; tests[*i].stage == stage; (*i)++) {
/*
* Some fetch protection override tests require that page 0
* be mapped, however, when the hosts tries to map that page via
* vm_vaddr_alloc, it may happen that some other page gets mapped
* instead.
* In order to skip these tests we detect this inside the guest
*/
skip = tests[*i].addr < (void *)4096 &&
tests[*i].expected != TRANSL_UNAVAIL &&
!mapped_0;
if (!skip) {
result = test_protection(tests[*i].addr, tests[*i].key);
GUEST_ASSERT_2(result == tests[*i].expected, *i, result);
}
}
return stage;
}
static void guest_code(void)
{
bool mapped_0;
int i = 0;
GUEST_ASSERT_EQ(set_storage_key(page_store_prot, 0x10), 0);
GUEST_ASSERT_EQ(set_storage_key(page_fetch_prot, 0x98), 0);
GUEST_SYNC(STAGE_INIT_SIMPLE);
GUEST_SYNC(perform_next_stage(&i, false));
/* Fetch-protection override */
mapped_0 = !set_storage_key((void *)0, 0x98);
GUEST_SYNC(STAGE_INIT_FETCH_PROT_OVERRIDE);
GUEST_SYNC(perform_next_stage(&i, mapped_0));
/* Storage-protection override */
GUEST_SYNC(perform_next_stage(&i, mapped_0));
}
#define HOST_SYNC(vmp, stage) \
({ \
struct kvm_vm *__vm = (vmp); \
struct ucall uc; \
int __stage = (stage); \
\
vcpu_run(__vm, VCPU_ID); \
get_ucall(__vm, VCPU_ID, &uc); \
if (uc.cmd == UCALL_ABORT) { \
TEST_FAIL("line %lu: %s, hints: %lu, %lu", uc.args[1], \
(const char *)uc.args[0], uc.args[2], uc.args[3]); \
} \
ASSERT_EQ(uc.cmd, UCALL_SYNC); \
ASSERT_EQ(uc.args[1], __stage); \
})
int main(int argc, char *argv[])
{
struct kvm_vm *vm;
struct kvm_run *run;
vm_vaddr_t guest_0_page;
vm = vm_create_default(VCPU_ID, 0, guest_code);
run = vcpu_state(vm, VCPU_ID);
HOST_SYNC(vm, STAGE_INIT_SIMPLE);
mprotect(addr_gva2hva(vm, (vm_vaddr_t)pages), PAGE_SIZE * 2, PROT_READ);
HOST_SYNC(vm, TEST_SIMPLE);
guest_0_page = vm_vaddr_alloc(vm, PAGE_SIZE, 0);
if (guest_0_page != 0)
print_skip("Did not allocate page at 0 for fetch protection override tests");
HOST_SYNC(vm, STAGE_INIT_FETCH_PROT_OVERRIDE);
if (guest_0_page == 0)
mprotect(addr_gva2hva(vm, (vm_vaddr_t)0), PAGE_SIZE, PROT_READ);
run->s.regs.crs[0] |= CR0_FETCH_PROTECTION_OVERRIDE;
run->kvm_dirty_regs = KVM_SYNC_CRS;
HOST_SYNC(vm, TEST_FETCH_PROT_OVERRIDE);
run->s.regs.crs[0] |= CR0_STORAGE_PROTECTION_OVERRIDE;
run->kvm_dirty_regs = KVM_SYNC_CRS;
HOST_SYNC(vm, TEST_STORAGE_PROT_OVERRIDE);
}
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