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 is EFER, in which only SCE might be unmasked. However, using the kvm_set_shared_msr for other purposes becomes impossible.
This patch keeps the masked bits unmodified while setting a shared msr. Signed-off-by: Nadav Amit <[email protected]> --- 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
