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fix: validate RDSEED against CPU feature #2401

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fix: validate RDSEED against CPU feature #2401

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5 changes: 2 additions & 3 deletions qemu/target/i386/cpu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -631,11 +631,10 @@ static CPUCacheInfo legacy_l3_cache = {
CPUID_7_0_EBX_BMI1 | CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ADX | \
CPUID_7_0_EBX_PCOMMIT | CPUID_7_0_EBX_CLFLUSHOPT | \
CPUID_7_0_EBX_CLWB | CPUID_7_0_EBX_MPX | CPUID_7_0_EBX_FSGSBASE | \
CPUID_7_0_EBX_ERMS)
CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_RDSEED)
/* missing:
CPUID_7_0_EBX_HLE, CPUID_7_0_EBX_AVX2,
CPUID_7_0_EBX_INVPCID, CPUID_7_0_EBX_RTM,
CPUID_7_0_EBX_RDSEED */
CPUID_7_0_EBX_INVPCID, CPUID_7_0_EBX_RTM */
#define TCG_7_0_ECX_FEATURES (CPUID_7_0_ECX_PKU | \
/* CPUID_7_0_ECX_OSPKE is dynamic */ \
CPUID_7_0_ECX_LA57)
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8 changes: 8 additions & 0 deletions qemu/target/i386/translate.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5845,12 +5845,20 @@ static target_ulong disas_insn(DisasContext *s, CPUState *cpu)
break;

case 7: /* RDSEED */
if (mod != 3 ||
(s->prefix & (PREFIX_LOCK | PREFIX_REPZ | PREFIX_REPNZ)) ||
!(s->cpuid_7_0_ebx_features & CPUID_7_0_EBX_RDSEED)) {
goto illegal_op;
}
goto do_rdrand;

case 6: /* RDRAND */
if (mod != 3 ||
(s->prefix & (PREFIX_LOCK | PREFIX_REPZ | PREFIX_REPNZ)) ||
!(s->cpuid_ext_features & CPUID_EXT_RDRAND)) {
goto illegal_op;
}
do_rdrand:
if (tb_cflags(s->base.tb) & CF_USE_ICOUNT) {
gen_io_start(tcg_ctx);
}
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25 changes: 25 additions & 0 deletions tests/unit/test_x86.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2377,6 +2377,30 @@ static void test_x86_hook_insn_rdtscp(void)
OK(uc_close(uc));
}

static void test_x86_rdseed(void)
{
char code[] = "\x48\x0F\xC7\xFB"; // RDSEED RBX
uc_engine *uc;

// RDSEED requires CPU support.
OK(uc_open(UC_ARCH_X86, UC_MODE_64, &uc));
OK(uc_ctl_set_cpu_model(uc, UC_CPU_X86_HASWELL));
OK(uc_mem_map(uc, code_start, code_len, UC_PROT_ALL));
OK(uc_mem_write(uc, code_start, code, sizeof(code) - 1));
uc_assert_err(UC_ERR_INSN_INVALID,
uc_emu_start(uc, code_start, code_start + sizeof(code) - 1,
0, 0));

OK(uc_close(uc));

// RDSEED executes on supported CPUs.
OK(uc_open(UC_ARCH_X86, UC_MODE_64, &uc));
OK(uc_ctl_set_cpu_model(uc, UC_CPU_X86_BROADWELL));
OK(uc_mem_map(uc, code_start, code_len, UC_PROT_ALL));
OK(uc_mem_write(uc, code_start, code, sizeof(code) - 1));
OK(uc_emu_start(uc, code_start, code_start + sizeof(code) - 1, 0, 0));
OK(uc_close(uc));
}
static int test_x86_hook_insn_wrmsr_cb(uc_engine *uc, void *user_data)
{
*(int *)user_data = 1;
Expand Down Expand Up @@ -2802,6 +2826,7 @@ TEST_LIST = {
{"test_x86_ro_segfault", test_x86_ro_segfault},
{"test_x86_hook_insn_rdtsc", test_x86_hook_insn_rdtsc},
{"test_x86_hook_insn_rdtscp", test_x86_hook_insn_rdtscp},
{"test_x86_rdseed", test_x86_rdseed},
{"test_x86_hook_insn_wrmsr", test_x86_hook_insn_wrmsr},
{"test_x86_hook_insn_rdmsr", test_x86_hook_insn_rdmsr},
{"test_x86_dr7", test_x86_dr7},
Expand Down
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