3.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx>
commit 2b29a9fdcb92bfc6b6f4c412d71505869de61a56 upstream.
Any uaccess between guest_enter and guest_exit could trigger a page fault,
the page fault handler would handle it as a guest fault and translate a
user address as guest address.
Signed-off-by: Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/kvm/kvm-s390.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -622,14 +622,25 @@ static int __vcpu_run(struct kvm_vcpu *v
kvm_s390_deliver_pending_interrupts(vcpu);
vcpu->arch.sie_block->icptcode = 0;
- preempt_disable();
- kvm_guest_enter();
- preempt_enable();
VCPU_EVENT(vcpu, 6, "entering sie flags %x",
atomic_read(&vcpu->arch.sie_block->cpuflags));
trace_kvm_s390_sie_enter(vcpu,
atomic_read(&vcpu->arch.sie_block->cpuflags));
+
+ /*
+ * As PF_VCPU will be used in fault handler, between guest_enter
+ * and guest_exit should be no uaccess.
+ */
+ preempt_disable();
+ kvm_guest_enter();
+ preempt_enable();
rc = sie64a(vcpu->arch.sie_block, vcpu->run->s.regs.gprs);
+ kvm_guest_exit();
+
+ VCPU_EVENT(vcpu, 6, "exit sie icptcode %d",
+ vcpu->arch.sie_block->icptcode);
+ trace_kvm_s390_sie_exit(vcpu, vcpu->arch.sie_block->icptcode);
+
if (rc) {
if (kvm_is_ucontrol(vcpu->kvm)) {
rc = SIE_INTERCEPT_UCONTROL;
@@ -639,10 +650,6 @@ static int __vcpu_run(struct kvm_vcpu *v
rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
}
}
- VCPU_EVENT(vcpu, 6, "exit sie icptcode %d",
- vcpu->arch.sie_block->icptcode);
- trace_kvm_s390_sie_exit(vcpu, vcpu->arch.sie_block->icptcode);
- kvm_guest_exit();
memcpy(&vcpu->run->s.regs.gprs[14], &vcpu->arch.sie_block->gg14, 16);
return rc;
--
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