xen-project/xen
1
0 Fork 0
mirror of https://github.com/xen-project/xen.git synced 2026-10-28 02:01:24 +01:00
Code Issues Activity

x86: miscellaneous emulator adjustments

Browse Source 
Defer fail_if()-s as much as possible (in favor of possibly generating
exceptions), and avoid generating exceptions when not strictly
necessary.

Avoid fail_if()-s for simple return code checks (making the code that
used them consistent with other, longer existing code).

Eliminate redundant generate_exception_if()-s checking lock_prefix
(which is already covered by the general check prior to decoding
operands).

Also fix the testing code to add PROT_EXEC for the mapping that is
intended to have instruction executed from.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
This commit is contained in:
Keir Fraser committed 2009-08-19 13:02:31 +01:00
1 parent b2c296e1c5
commit c88b1e06d5
2 files changed
+40 -50
Download Patch File Download Diff File Expand all files Collapse all files

No files matched your search

tools/tests/test_x86_emulator.c
+1 -1
View File
@@ -76,7 +76,7 @@ int main(int argc, char **argv)
ctxt.addr_size = 32;
ctxt.sp_size = 32;
res = mmap((void *)0x100000, MMAP_SZ, PROT_READ|PROT_WRITE,
res = mmap((void *)0x100000, MMAP_SZ, PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_FIXED|MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
if ( res == MAP_FAILED )
{
xen/arch/x86/x86_emulate/x86_emulate.c
+39 -49
View File
@@ -3583,21 +3583,17 @@ x86_emulate(
struct segment_register cs = { 0 }, ss = { 0 };
int rc;
fail_if(ops->read_msr == NULL);
fail_if(ops->read_segment == NULL);
fail_if(ops->write_segment == NULL);
generate_exception_if(in_realmode(ctxt, ops), EXC_UD, 0);
generate_exception_if(!in_protmode(ctxt, ops), EXC_UD, 0);
generate_exception_if(lock_prefix, EXC_UD, 0);
/* Inject #UD if syscall/sysret are disabled. */
rc = ops->read_msr(MSR_EFER, &msr_content, ctxt);
fail_if(rc != 0);
fail_if(ops->read_msr == NULL);
if ( (rc = ops->read_msr(MSR_EFER, &msr_content, ctxt)) != 0 )
goto done;
generate_exception_if((msr_content & EFER_SCE) == 0, EXC_UD, 0);
rc = ops->read_msr(MSR_STAR, &msr_content, ctxt);
fail_if(rc != 0);
if ( (rc = ops->read_msr(MSR_STAR, &msr_content, ctxt)) != 0 )
goto done;
msr_content >>= 32;
cs.sel = (uint16_t)(msr_content & 0xfffc);
@@ -3617,27 +3613,27 @@ x86_emulate(
_regs.rcx = _regs.rip;
_regs.r11 = _regs.eflags & ~EFLG_RF;
rc = ops->read_msr(mode_64bit() ? MSR_LSTAR : MSR_CSTAR,
&msr_content, ctxt);
fail_if(rc != 0);
if ( (rc = ops->read_msr(mode_64bit() ? MSR_LSTAR : MSR_CSTAR,
&msr_content, ctxt)) != 0 )
goto done;
_regs.rip = msr_content;
rc = ops->read_msr(MSR_FMASK, &msr_content, ctxt);
fail_if(rc != 0);
if ( (rc = ops->read_msr(MSR_FMASK, &msr_content, ctxt)) != 0 )
goto done;
_regs.eflags &= ~(msr_content | EFLG_RF);
}
else
#endif
{
rc = ops->read_msr(MSR_STAR, &msr_content, ctxt);
fail_if(rc != 0);
if ( (rc = ops->read_msr(MSR_STAR, &msr_content, ctxt)) != 0 )
goto done;
_regs.ecx = _regs.eip;
_regs.eip = (uint32_t)msr_content;
_regs.eflags &= ~(EFLG_VM | EFLG_IF | EFLG_RF);
}
fail_if(ops->write_segment == NULL);
if ( (rc = ops->write_segment(x86_seg_cs, &cs, ctxt)) ||
(rc = ops->write_segment(x86_seg_ss, &ss, ctxt)) )
goto done;
@@ -3717,10 +3713,13 @@ x86_emulate(
case 0x31: /* rdtsc */ {
unsigned long cr4;
uint64_t val;
fail_if(ops->read_cr == NULL);
if ( (rc = ops->read_cr(4, &cr4, ctxt)) )
goto done;
generate_exception_if((cr4 & CR4_TSD) && !mode_ring0(), EXC_GP, 0);
if ( !mode_ring0() )
{
fail_if(ops->read_cr == NULL);
if ( (rc = ops->read_cr(4, &cr4, ctxt)) )
goto done;
generate_exception_if(cr4 & CR4_TSD, EXC_GP, 0);
}
fail_if(ops->read_msr == NULL);
if ( (rc = ops->read_msr(MSR_TSC, &val, ctxt)) != 0 )
goto done;
@@ -3751,17 +3750,13 @@ x86_emulate(
struct segment_register cs, ss;
int rc;
fail_if(ops->read_msr == NULL);
fail_if(ops->read_segment == NULL);
fail_if(ops->write_segment == NULL);
generate_exception_if(mode_ring0(), EXC_GP, 0);
generate_exception_if(in_realmode(ctxt, ops), EXC_GP, 0);
generate_exception_if(!in_protmode(ctxt, ops), EXC_GP, 0);
generate_exception_if(lock_prefix, EXC_UD, 0);
rc = ops->read_msr(MSR_SYSENTER_CS, &msr_content, ctxt);
fail_if(rc != 0);
fail_if(ops->read_msr == NULL);
if ( (rc = ops->read_msr(MSR_SYSENTER_CS, &msr_content, ctxt)) != 0 )
goto done;
if ( mode_64bit() )
generate_exception_if(msr_content == 0, EXC_GP, 0);
@@ -3770,6 +3765,7 @@ x86_emulate(
_regs.eflags &= ~(EFLG_VM | EFLG_IF | EFLG_RF);
fail_if(ops->read_segment == NULL);
ops->read_segment(x86_seg_cs, &cs, ctxt);
cs.sel = (uint16_t)msr_content & ~3; /* SELECTOR_RPL_MASK */
cs.base = 0; /* flat segment */
@@ -3787,17 +3783,17 @@ x86_emulate(
cs.attr.fields.l = 1;
}
rc = ops->write_segment(x86_seg_cs, &cs, ctxt);
fail_if(rc != 0);
rc = ops->write_segment(x86_seg_ss, &ss, ctxt);
fail_if(rc != 0);
fail_if(ops->write_segment == NULL);
if ( (rc = ops->write_segment(x86_seg_cs, &cs, ctxt)) != 0 ||
(rc = ops->write_segment(x86_seg_ss, &ss, ctxt)) != 0 )
goto done;
rc = ops->read_msr(MSR_SYSENTER_EIP, &msr_content, ctxt);
fail_if(rc != 0);
if ( (rc = ops->read_msr(MSR_SYSENTER_EIP, &msr_content, ctxt)) != 0 )
goto done;
_regs.eip = msr_content;
rc = ops->read_msr(MSR_SYSENTER_ESP, &msr_content, ctxt);
fail_if(rc != 0);
if ( (rc = ops->read_msr(MSR_SYSENTER_ESP, &msr_content, ctxt)) != 0 )
goto done;
_regs.esp = msr_content;
break;
@@ -3809,19 +3805,13 @@ x86_emulate(
int user64 = !!(rex_prefix & 8); /* REX.W */
int rc;
fail_if(ops->read_msr == NULL);
fail_if(ops->read_segment == NULL);
fail_if(ops->write_segment == NULL);
generate_exception_if(!mode_ring0(), EXC_GP, 0);
generate_exception_if(in_realmode(ctxt, ops), EXC_GP, 0);
generate_exception_if(!in_protmode(ctxt, ops), EXC_GP, 0);
generate_exception_if(lock_prefix, EXC_UD, 0);
rc = ops->read_msr(MSR_SYSENTER_CS, &msr_content, ctxt);
fail_if(rc != 0);
rc = ops->read_segment(x86_seg_cs, &cs, ctxt);
fail_if(rc != 0);
fail_if(ops->read_msr == NULL);
if ( (rc = ops->read_msr(MSR_SYSENTER_CS, &msr_content, ctxt)) != 0 )
goto done;
if ( user64 )
{
@@ -3852,10 +3842,10 @@ x86_emulate(
cs.attr.fields.l = 1;
}
rc = ops->write_segment(x86_seg_cs, &cs, ctxt);
fail_if(rc != 0);
rc = ops->write_segment(x86_seg_ss, &ss, ctxt);
fail_if(rc != 0);
fail_if(ops->write_segment == NULL);
if ( (rc = ops->write_segment(x86_seg_cs, &cs, ctxt)) != 0 ||
(rc = ops->write_segment(x86_seg_ss, &ss, ctxt)) != 0 )
goto done;
_regs.eip = _regs.edx;
_regs.esp = _regs.ecx;
Reference in new issue
xen-project/xen
Block a user
Blocking a user prevents them from interacting with repositories, such as opening or commenting on pull requests or issues. Learn more about blocking a user.

The note is not visible to the blocked user.