Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-01 01:31:44 +00:00
Code Issues Packages Projects Releases Wiki Activity

KVM: x86 emulator: fix hypercall return value on AMD

Browse Source 
The hypercall instructions on Intel and AMD are different.  KVM allows the
guest to choose one or the other (the default is Intel), and if the guest
chooses incorrectly, KVM will patch it at runtime to select the correct
instruction.  This allows live migration between Intel and AMD machines.

This patching occurs in the x86 emulator.  The current code also executes
the hypercall.  Unfortunately, the tail end of the x86 emulator code also
executes, overwriting the return value of the hypercall with the original
contents of rax (which happens to be the hypercall number).

Fix not by executing the hypercall in the emulator context; instead let the
guest reissue the patched instruction and execute the hypercall via the
normal path.

Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Avi Kivity 2008-05-21 15:34:25 +03:00
parent f20d275298
commit 33e3885de2
1 changed files with 2 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/x86/kvm/x86_emulate.c
View File

@ -1727,7 +1727,8 @@ twobyte_insn:
if (rc)
goto done;
kvm_emulate_hypercall(ctxt->vcpu);
/* Let the processor re-execute the fixed hypercall */
c->eip = ctxt->vcpu->arch.rip;
/* Disable writeback. */
c->dst.type = OP_NONE;
break;