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authorPaul Mackerras <paulus@ozlabs.org>2018-06-07 18:07:06 +1000
committerPaul Mackerras <paulus@ozlabs.org>2018-06-13 09:45:28 +1000
commit4f169d21181faad87a6cdb288742e08c808ec0ef (patch)
tree517501be92513ab61b3d4e873f2b2c0d76bba971
parenta50623fb57002207b9b2636e1d3bd5cf17a3e74f (diff)
downloadlinux-4f169d21181faad87a6cdb288742e08c808ec0ef.tar.bz2
KVM: PPC: Book3S PR: Don't let PAPR guest set MSR hypervisor bit
PAPR guests run in supervisor mode and should not be able to set the MSR HV (hypervisor mode) bit or clear the ME (machine check enable) bit by mtmsrd or any other means. To enforce this, we force MSR_HV off and MSR_ME on in kvmppc_set_msr_pr. Without this, the guest can appear to be in hypervisor mode to itself and to userspace. This has been observed to cause a crash in QEMU when it tries to deliver a system reset interrupt to the guest. Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
-rw-r--r--arch/powerpc/kvm/book3s_pr.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index e8036ddeded1..5c99b84e0856 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -456,6 +456,10 @@ static void kvmppc_set_msr_pr(struct kvm_vcpu *vcpu, u64 msr)
{
ulong old_msr;
+ /* For PAPR guest, make sure MSR reflects guest mode */
+ if (vcpu->arch.papr_enabled)
+ msr = (msr & ~MSR_HV) | MSR_ME;
+
#ifdef EXIT_DEBUG
printk(KERN_INFO "KVM: Set MSR to 0x%llx\n", msr);
#endif