244 lines
7.1 KiB
C
244 lines
7.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Test TEST PROTECTION emulation.
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*
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* Copyright IBM Corp. 2021
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*/
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#include <sys/mman.h>
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#include "test_util.h"
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#include "kvm_util.h"
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#include "kselftest.h"
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#define PAGE_SHIFT 12
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#define PAGE_SIZE (1 << PAGE_SHIFT)
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#define CR0_FETCH_PROTECTION_OVERRIDE (1UL << (63 - 38))
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#define CR0_STORAGE_PROTECTION_OVERRIDE (1UL << (63 - 39))
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static __aligned(PAGE_SIZE) uint8_t pages[2][PAGE_SIZE];
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static uint8_t *const page_store_prot = pages[0];
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static uint8_t *const page_fetch_prot = pages[1];
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/* Nonzero return value indicates that address not mapped */
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static int set_storage_key(void *addr, uint8_t key)
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{
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int not_mapped = 0;
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asm volatile (
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"lra %[addr], 0(0,%[addr])\n"
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" jz 0f\n"
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" llill %[not_mapped],1\n"
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" j 1f\n"
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"0: sske %[key], %[addr]\n"
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"1:"
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: [addr] "+&a" (addr), [not_mapped] "+r" (not_mapped)
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: [key] "r" (key)
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: "cc"
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);
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return -not_mapped;
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}
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enum permission {
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READ_WRITE = 0,
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READ = 1,
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RW_PROTECTED = 2,
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TRANSL_UNAVAIL = 3,
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};
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static enum permission test_protection(void *addr, uint8_t key)
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{
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uint64_t mask;
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asm volatile (
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"tprot %[addr], 0(%[key])\n"
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" ipm %[mask]\n"
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: [mask] "=r" (mask)
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: [addr] "Q" (*(char *)addr),
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[key] "a" (key)
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: "cc"
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);
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return (enum permission)(mask >> 28);
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}
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enum stage {
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STAGE_INIT_SIMPLE,
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TEST_SIMPLE,
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STAGE_INIT_FETCH_PROT_OVERRIDE,
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TEST_FETCH_PROT_OVERRIDE,
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TEST_STORAGE_PROT_OVERRIDE,
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STAGE_END /* must be the last entry (it's the amount of tests) */
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};
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struct test {
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enum stage stage;
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void *addr;
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uint8_t key;
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enum permission expected;
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} tests[] = {
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/*
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* We perform each test in the array by executing TEST PROTECTION on
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* the specified addr with the specified key and checking if the returned
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* permissions match the expected value.
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* Both guest and host cooperate to set up the required test conditions.
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* A central condition is that the page targeted by addr has to be DAT
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* protected in the host mappings, in order for KVM to emulate the
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* TEST PROTECTION instruction.
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* Since the page tables are shared, the host uses mprotect to achieve
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* this.
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*
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* Test resulting in RW_PROTECTED/TRANSL_UNAVAIL will be interpreted
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* by SIE, not KVM, but there is no harm in testing them also.
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* See Enhanced Suppression-on-Protection Facilities in the
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* Interpretive-Execution Mode
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*/
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/*
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* guest: set storage key of page_store_prot to 1
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* storage key of page_fetch_prot to 9 and enable
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* protection for it
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* STAGE_INIT_SIMPLE
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* host: write protect both via mprotect
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*/
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/* access key 0 matches any storage key -> RW */
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{ TEST_SIMPLE, page_store_prot, 0x00, READ_WRITE },
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/* access key matches storage key -> RW */
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{ TEST_SIMPLE, page_store_prot, 0x10, READ_WRITE },
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/* mismatched keys, but no fetch protection -> RO */
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{ TEST_SIMPLE, page_store_prot, 0x20, READ },
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/* access key 0 matches any storage key -> RW */
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{ TEST_SIMPLE, page_fetch_prot, 0x00, READ_WRITE },
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/* access key matches storage key -> RW */
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{ TEST_SIMPLE, page_fetch_prot, 0x90, READ_WRITE },
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/* mismatched keys, fetch protection -> inaccessible */
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{ TEST_SIMPLE, page_fetch_prot, 0x10, RW_PROTECTED },
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/* page 0 not mapped yet -> translation not available */
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{ TEST_SIMPLE, (void *)0x00, 0x10, TRANSL_UNAVAIL },
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/*
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* host: try to map page 0
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* guest: set storage key of page 0 to 9 and enable fetch protection
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* STAGE_INIT_FETCH_PROT_OVERRIDE
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* host: write protect page 0
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* enable fetch protection override
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*/
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/* mismatched keys, fetch protection, but override applies -> RO */
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{ TEST_FETCH_PROT_OVERRIDE, (void *)0x00, 0x10, READ },
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/* mismatched keys, fetch protection, override applies to 0-2048 only -> inaccessible */
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{ TEST_FETCH_PROT_OVERRIDE, (void *)2049, 0x10, RW_PROTECTED },
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/*
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* host: enable storage protection override
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*/
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/* mismatched keys, but override applies (storage key 9) -> RW */
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{ TEST_STORAGE_PROT_OVERRIDE, page_fetch_prot, 0x10, READ_WRITE },
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/* mismatched keys, no fetch protection, override doesn't apply -> RO */
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{ TEST_STORAGE_PROT_OVERRIDE, page_store_prot, 0x20, READ },
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/* mismatched keys, but override applies (storage key 9) -> RW */
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{ TEST_STORAGE_PROT_OVERRIDE, (void *)2049, 0x10, READ_WRITE },
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/* end marker */
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{ STAGE_END, 0, 0, 0 },
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};
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static enum stage perform_next_stage(int *i, bool mapped_0)
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{
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enum stage stage = tests[*i].stage;
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enum permission result;
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bool skip;
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for (; tests[*i].stage == stage; (*i)++) {
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/*
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* Some fetch protection override tests require that page 0
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* be mapped, however, when the hosts tries to map that page via
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* vm_vaddr_alloc, it may happen that some other page gets mapped
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* instead.
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* In order to skip these tests we detect this inside the guest
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*/
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skip = tests[*i].addr < (void *)4096 &&
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tests[*i].expected != TRANSL_UNAVAIL &&
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!mapped_0;
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if (!skip) {
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result = test_protection(tests[*i].addr, tests[*i].key);
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GUEST_ASSERT_2(result == tests[*i].expected, *i, result);
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}
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}
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return stage;
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}
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static void guest_code(void)
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{
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bool mapped_0;
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int i = 0;
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GUEST_ASSERT_EQ(set_storage_key(page_store_prot, 0x10), 0);
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GUEST_ASSERT_EQ(set_storage_key(page_fetch_prot, 0x98), 0);
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GUEST_SYNC(STAGE_INIT_SIMPLE);
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GUEST_SYNC(perform_next_stage(&i, false));
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/* Fetch-protection override */
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mapped_0 = !set_storage_key((void *)0, 0x98);
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GUEST_SYNC(STAGE_INIT_FETCH_PROT_OVERRIDE);
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GUEST_SYNC(perform_next_stage(&i, mapped_0));
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/* Storage-protection override */
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GUEST_SYNC(perform_next_stage(&i, mapped_0));
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}
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#define HOST_SYNC_NO_TAP(vcpup, stage) \
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({ \
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struct kvm_vcpu *__vcpu = (vcpup); \
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struct ucall uc; \
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int __stage = (stage); \
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\
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vcpu_run(__vcpu); \
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get_ucall(__vcpu, &uc); \
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if (uc.cmd == UCALL_ABORT) \
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REPORT_GUEST_ASSERT_2(uc, "hints: %lu, %lu"); \
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ASSERT_EQ(uc.cmd, UCALL_SYNC); \
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ASSERT_EQ(uc.args[1], __stage); \
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})
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#define HOST_SYNC(vcpu, stage) \
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({ \
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HOST_SYNC_NO_TAP(vcpu, stage); \
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ksft_test_result_pass("" #stage "\n"); \
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})
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int main(int argc, char *argv[])
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{
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struct kvm_vcpu *vcpu;
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struct kvm_vm *vm;
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struct kvm_run *run;
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vm_vaddr_t guest_0_page;
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ksft_print_header();
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ksft_set_plan(STAGE_END);
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vm = vm_create_with_one_vcpu(&vcpu, guest_code);
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run = vcpu->run;
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HOST_SYNC(vcpu, STAGE_INIT_SIMPLE);
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mprotect(addr_gva2hva(vm, (vm_vaddr_t)pages), PAGE_SIZE * 2, PROT_READ);
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HOST_SYNC(vcpu, TEST_SIMPLE);
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guest_0_page = vm_vaddr_alloc(vm, PAGE_SIZE, 0);
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if (guest_0_page != 0) {
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/* Use NO_TAP so we don't get a PASS print */
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HOST_SYNC_NO_TAP(vcpu, STAGE_INIT_FETCH_PROT_OVERRIDE);
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ksft_test_result_skip("STAGE_INIT_FETCH_PROT_OVERRIDE - "
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"Did not allocate page at 0\n");
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} else {
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HOST_SYNC(vcpu, STAGE_INIT_FETCH_PROT_OVERRIDE);
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}
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if (guest_0_page == 0)
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mprotect(addr_gva2hva(vm, (vm_vaddr_t)0), PAGE_SIZE, PROT_READ);
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run->s.regs.crs[0] |= CR0_FETCH_PROTECTION_OVERRIDE;
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run->kvm_dirty_regs = KVM_SYNC_CRS;
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HOST_SYNC(vcpu, TEST_FETCH_PROT_OVERRIDE);
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run->s.regs.crs[0] |= CR0_STORAGE_PROTECTION_OVERRIDE;
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run->kvm_dirty_regs = KVM_SYNC_CRS;
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HOST_SYNC(vcpu, TEST_STORAGE_PROT_OVERRIDE);
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kvm_vm_free(vm);
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ksft_finished(); /* Print results and exit() accordingly */
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}
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