diff mbox

[PULL,45/63] KVM: PPC: Book3S PR: Take SRCU read lock around RTAS kvm_read_guest() call

Message ID 1406884714-33099-46-git-send-email-agraf@suse.de (mailing list archive)
State New, archived
Headers show

Commit Message

Alexander Graf Aug. 1, 2014, 9:18 a.m. UTC 
From: Paul Mackerras <paulus@samba.org>

This does for PR KVM what c9438092cae4 ("KVM: PPC: Book3S HV: Take SRCU
read lock around kvm_read_guest() call") did for HV KVM, that is,
eliminate a "suspicious rcu_dereference_check() usage!" warning by
taking the SRCU lock around the call to kvmppc_rtas_hcall().

It also fixes a return of RESUME_HOST to return EMULATE_FAIL instead,
since kvmppc_h_pr() is supposed to return EMULATE_* values.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 arch/powerpc/kvm/book3s_pr_papr.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
diff mbox

Patch

diff --git a/arch/powerpc/kvm/book3s_pr_papr.c b/arch/powerpc/kvm/book3s_pr_papr.c
index 6d0143f..ce3c893 100644
--- a/arch/powerpc/kvm/book3s_pr_papr.c
+++ b/arch/powerpc/kvm/book3s_pr_papr.c
@@ -267,6 +267,8 @@  static int kvmppc_h_pr_xics_hcall(struct kvm_vcpu *vcpu, u32 cmd)
 
 int kvmppc_h_pr(struct kvm_vcpu *vcpu, unsigned long cmd)
 {
+	int rc, idx;
+
 	if (cmd <= MAX_HCALL_OPCODE &&
 	    !test_bit(cmd/4, vcpu->kvm->arch.enabled_hcalls))
 		return EMULATE_FAIL;
@@ -299,8 +301,11 @@  int kvmppc_h_pr(struct kvm_vcpu *vcpu, unsigned long cmd)
 		break;
 	case H_RTAS:
 		if (list_empty(&vcpu->kvm->arch.rtas_tokens))
-			return RESUME_HOST;
-		if (kvmppc_rtas_hcall(vcpu))
+			break;
+		idx = srcu_read_lock(&vcpu->kvm->srcu);
+		rc = kvmppc_rtas_hcall(vcpu);
+		srcu_read_unlock(&vcpu->kvm->srcu, idx);
+		if (rc)
 			break;
 		kvmppc_set_gpr(vcpu, 3, 0);
 		return EMULATE_DONE;