Hi Nadav, On Wed, Aug 20, 2014 at 03:11:51PM +0300, Nadav Amit wrote: >Currently, when an msr is updated using kvm_set_shared_msr the masked bits are >zeroed. This behavior is currently valid since the only MSR with partial mask Why zeroed? vmx_vcpu_setup() set all mask to -1ull. >is EFER, in which only SCE might be unmasked. However, using the Do you mean SCE might be masked? >kvm_set_shared_msr for other purposes becomes impossible. > >This patch keeps the masked bits unmodified while setting a shared msr. > Do you mean "keeps the unmasked bits unmodified" instead of "keeps the masked bits unmodified"? Regards, Wanpeng Li >Signed-off-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx> >--- > arch/x86/kvm/x86.c | 1 + > 1 file changed, 1 insertion(+) > >diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >index 5f5edb6..ee42410 100644 >--- a/arch/x86/kvm/x86.c >+++ b/arch/x86/kvm/x86.c >@@ -236,6 +236,7 @@ void kvm_set_shared_msr(unsigned slot, u64 value, u64 mask) > > if (((value ^ smsr->values[slot].curr) & mask) == 0) > return; >+ value = (smsr->values[slot].curr & ~mask) | (value & mask); > smsr->values[slot].curr = value; > wrmsrl(shared_msrs_global.msrs[slot], value); > if (!smsr->registered) { >-- >1.9.1 > >-- >To unsubscribe from this list: send the line "unsubscribe kvm" in >the body of a message to majordomo@xxxxxxxxxxxxxxx >More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html