Users of handle_exception() should always save and restore the handlers.
Suggested-by: Sean Christopherson seanjc@google.com Signed-off-by: Michal Luczaj mhal@rbox.co --- v1 -> v2: No changes
x86/emulator.c | 78 ++++++++++++++++++++++++++------------------------ 1 file changed, 41 insertions(+), 37 deletions(-)
diff --git a/x86/emulator.c b/x86/emulator.c index cd78e3c..769a049 100644 --- a/x86/emulator.c +++ b/x86/emulator.c @@ -710,6 +710,7 @@ static __attribute__((target("sse2"))) void test_sse_exceptions(void *cross_mem) void *page2 = (void *)(&bytes[4096]); struct pte_search search; pteval_t orig_pte; + handler old;
// setup memory for unaligned access mem = (uint32_t *)(&bytes[8]); @@ -725,10 +726,10 @@ static __attribute__((target("sse2"))) void test_sse_exceptions(void *cross_mem) asm("movupd %1, %0" : "=m"(*mem) : "x"(vv) : "memory"); report(sseeq(v, mem), "movupd unaligned"); exceptions = 0; - handle_exception(GP_VECTOR, unaligned_movaps_handler); + old = handle_exception(GP_VECTOR, unaligned_movaps_handler); asm("movaps %1, %0\n\t unaligned_movaps_cont:" : "=m"(*mem) : "x"(vv)); - handle_exception(GP_VECTOR, 0); + handle_exception(GP_VECTOR, old); report(exceptions == 1, "unaligned movaps exception");
// setup memory for cross page access @@ -746,10 +747,10 @@ static __attribute__((target("sse2"))) void test_sse_exceptions(void *cross_mem) invlpg(page2);
exceptions = 0; - handle_exception(PF_VECTOR, cross_movups_handler); + old = handle_exception(PF_VECTOR, cross_movups_handler); asm("movups %1, %0\n\t cross_movups_cont:" : "=m"(*mem) : "x"(vv) : "memory"); - handle_exception(PF_VECTOR, 0); + handle_exception(PF_VECTOR, old); report(exceptions == 1, "movups crosspage exception");
// restore invalidated page @@ -817,36 +818,38 @@ static void advance_rip_and_note_exception(struct ex_regs *regs)
static void test_mmx_movq_mf(uint64_t *mem) { - /* movq %mm0, (%rax) */ - extern char movq_start, movq_end; - - uint16_t fcw = 0; /* all exceptions unmasked */ - write_cr0(read_cr0() & ~6); /* TS, EM */ - exceptions = 0; - handle_exception(MF_VECTOR, advance_rip_and_note_exception); - asm volatile("fninit; fldcw %0" : : "m"(fcw)); - asm volatile("fldz; fldz; fdivp"); /* generate exception */ - - rip_advance = &movq_end - &movq_start; - asm(KVM_FEP "movq_start: movq %mm0, (%rax); movq_end:"); - /* exit MMX mode */ - asm volatile("fnclex; emms"); - report(exceptions == 1, "movq mmx generates #MF"); - handle_exception(MF_VECTOR, 0); + /* movq %mm0, (%rax) */ + extern char movq_start, movq_end; + handler old; + + uint16_t fcw = 0; /* all exceptions unmasked */ + write_cr0(read_cr0() & ~6); /* TS, EM */ + exceptions = 0; + old = handle_exception(MF_VECTOR, advance_rip_and_note_exception); + asm volatile("fninit; fldcw %0" : : "m"(fcw)); + asm volatile("fldz; fldz; fdivp"); /* generate exception */ + + rip_advance = &movq_end - &movq_start; + asm(KVM_FEP "movq_start: movq %mm0, (%rax); movq_end:"); + /* exit MMX mode */ + asm volatile("fnclex; emms"); + report(exceptions == 1, "movq mmx generates #MF"); + handle_exception(MF_VECTOR, old); }
static void test_jmp_noncanonical(uint64_t *mem) { extern char nc_jmp_start, nc_jmp_end; + handler old;
*mem = 0x1111111111111111ul;
exceptions = 0; rip_advance = &nc_jmp_end - &nc_jmp_start; - handle_exception(GP_VECTOR, advance_rip_and_note_exception); + old = handle_exception(GP_VECTOR, advance_rip_and_note_exception); asm volatile ("nc_jmp_start: jmp *%0; nc_jmp_end:" : : "m"(*mem)); report(exceptions == 1, "jump to non-canonical address"); - handle_exception(GP_VECTOR, 0); + handle_exception(GP_VECTOR, old); }
static void test_movabs(uint64_t *mem) @@ -979,22 +982,23 @@ static void ss_bad_rpl(struct ex_regs *regs)
static void test_sreg(volatile uint16_t *mem) { - u16 ss = read_ss(); + u16 ss = read_ss(); + handler old;
- // check for null segment load - *mem = 0; - asm volatile("mov %0, %%ss" : : "m"(*mem)); - report(read_ss() == 0, "mov null, %%ss"); - - // check for exception when ss.rpl != cpl on null segment load - exceptions = 0; - handle_exception(GP_VECTOR, ss_bad_rpl); - *mem = 3; - asm volatile("mov %0, %%ss; ss_bad_rpl_cont:" : : "m"(*mem)); - report(exceptions == 1 && read_ss() == 0, - "mov null, %%ss (with ss.rpl != cpl)"); - handle_exception(GP_VECTOR, 0); - write_ss(ss); + // check for null segment load + *mem = 0; + asm volatile("mov %0, %%ss" : : "m"(*mem)); + report(read_ss() == 0, "mov null, %%ss"); + + // check for exception when ss.rpl != cpl on null segment load + exceptions = 0; + old = handle_exception(GP_VECTOR, ss_bad_rpl); + *mem = 3; + asm volatile("mov %0, %%ss; ss_bad_rpl_cont:" : : "m"(*mem)); + report(exceptions == 1 && read_ss() == 0, + "mov null, %%ss (with ss.rpl != cpl)"); + handle_exception(GP_VECTOR, old); + write_ss(ss); }
static uint64_t usr_gs_mov(void)