From e59d24e61269de34d79d2f39d3d581c219ac7a94 Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Thu, 6 Feb 2014 17:36:56 +0100 Subject: [PATCH] KVM: PPC: Book3S HV: Fix incorrect userspace exit on ioeventfd write When the guest does an MMIO write which is handled successfully by an ioeventfd, ioeventfd_write() returns 0 (success) and kvmppc_handle_store() returns EMULATE_DONE. Then kvmppc_emulate_mmio() converts EMULATE_DONE to RESUME_GUEST_NV and this causes an exit from the loop in kvmppc_vcpu_run_hv(), causing an exit back to userspace with a bogus exit reason code, typically causing userspace (e.g. qemu) to crash with a message about an unknown exit code. This adds handling of RESUME_GUEST_NV in kvmppc_vcpu_run_hv() in order to fix that. For generality, we define a helper to check for either of the return-to-guest codes we use, RESUME_GUEST and RESUME_GUEST_NV, to make it easy to check for either and provide one place to update if any other return-to-guest code gets defined in future. Since it only affects Book3S HV for now, the helper is added to the kvm_book3s.h header file. We use the helper in two places in kvmppc_run_core() as well for future-proofing, though we don't see RESUME_GUEST_NV in either place at present. [paulus@samba.org - combined 4 patches into one, rewrote description] Suggested-by: Paul Mackerras Signed-off-by: Alexey Kardashevskiy Signed-off-by: Greg Kurz Signed-off-by: Paul Mackerras --- arch/powerpc/include/asm/kvm_book3s.h | 5 +++++ arch/powerpc/kvm/book3s_hv.c | 6 +++--- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h index 83851aabfdc8..bb1e38a23ac7 100644 --- a/arch/powerpc/include/asm/kvm_book3s.h +++ b/arch/powerpc/include/asm/kvm_book3s.h @@ -304,6 +304,11 @@ static inline ulong kvmppc_get_fault_dar(struct kvm_vcpu *vcpu) return vcpu->arch.fault_dar; } +static inline bool is_kvmppc_resume_guest(int r) +{ + return (r == RESUME_GUEST || r == RESUME_GUEST_NV); +} + /* Magic register values loaded into r3 and r4 before the 'sc' assembly * instruction for the OSI hypercalls */ #define OSI_SC_MAGIC_R3 0x113724FA diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 17fc9496b6ac..3b498d942a22 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -1530,7 +1530,7 @@ static void kvmppc_run_core(struct kvmppc_vcore *vc) vcpu->arch.trap = 0; if (vcpu->arch.ceded) { - if (ret != RESUME_GUEST) + if (!is_kvmppc_resume_guest(ret)) kvmppc_end_cede(vcpu); else kvmppc_set_timer(vcpu); @@ -1541,7 +1541,7 @@ static void kvmppc_run_core(struct kvmppc_vcore *vc) vc->vcore_state = VCORE_INACTIVE; list_for_each_entry_safe(vcpu, vnext, &vc->runnable_threads, arch.run_list) { - if (vcpu->arch.ret != RESUME_GUEST) { + if (!is_kvmppc_resume_guest(vcpu->arch.ret)) { kvmppc_remove_runnable(vc, vcpu); wake_up(&vcpu->arch.cpu_run); } @@ -1731,7 +1731,7 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu) vcpu->arch.fault_dar, vcpu->arch.fault_dsisr); srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx); } - } while (r == RESUME_GUEST); + } while (is_kvmppc_resume_guest(r)); out: vcpu->arch.state = KVMPPC_VCPU_NOTREADY; -- 2.34.1