Mukesh Rathor
2014-08-05 01:33:37 UTC
Hi,
On AMD, clts/lmsw will cause "mov cr" vmexit, but unlike intel, they
can't be handled via svm_vmexit_do_cr_access and are emulated thru
handle_mmio() which is a problem for pvh because of:
handle_mmio():
..
ASSERT(!is_pvh_vcpu(curr));
AMD CR intercepts in svm.c:
case VMEXIT_CR0_READ ... VMEXIT_CR15_READ:
case VMEXIT_CR0_WRITE ... VMEXIT_CR15_WRITE:
if ( cpu_has_svm_decode && (vmcb->exitinfo1 & (1ULL << 63)) )
svm_vmexit_do_cr_access(vmcb, regs);
else if ( !handle_mmio() ) <==========
hvm_inject_hw_exception(TRAP_gp_fault, 0);
break;
Soooo, this leaves no choice but to make the ASSERT conditional
for intel only, and let handle_mmio go thru x86_emulate and let
x86_emulate fail for anything other than lmsw/clts? I was thinking
something like:
x86_emulate()
int fail_pvh_emul = 1;
...
case lmsw/clts:
.....
fail_pvh_emul = 0;
then
done:
if (fail_pvh_emul)
rc = X86EMUL_UNHANDLEABLE;
return rc;
Or, should I just create a new function for clts/lmsw and call it
directly from vmexit switch itself?
Can't think of any other clever way to do this... thoughts/suggestions?
thanks,
Mukesh
On AMD, clts/lmsw will cause "mov cr" vmexit, but unlike intel, they
can't be handled via svm_vmexit_do_cr_access and are emulated thru
handle_mmio() which is a problem for pvh because of:
handle_mmio():
..
ASSERT(!is_pvh_vcpu(curr));
AMD CR intercepts in svm.c:
case VMEXIT_CR0_READ ... VMEXIT_CR15_READ:
case VMEXIT_CR0_WRITE ... VMEXIT_CR15_WRITE:
if ( cpu_has_svm_decode && (vmcb->exitinfo1 & (1ULL << 63)) )
svm_vmexit_do_cr_access(vmcb, regs);
else if ( !handle_mmio() ) <==========
hvm_inject_hw_exception(TRAP_gp_fault, 0);
break;
Soooo, this leaves no choice but to make the ASSERT conditional
for intel only, and let handle_mmio go thru x86_emulate and let
x86_emulate fail for anything other than lmsw/clts? I was thinking
something like:
x86_emulate()
int fail_pvh_emul = 1;
...
case lmsw/clts:
.....
fail_pvh_emul = 0;
then
done:
if (fail_pvh_emul)
rc = X86EMUL_UNHANDLEABLE;
return rc;
Or, should I just create a new function for clts/lmsw and call it
directly from vmexit switch itself?
Can't think of any other clever way to do this... thoughts/suggestions?
thanks,
Mukesh