[RFC PATCH] riscv: kvm: return SBI_ERR_FAILURE for PMU shmem OOM

[Osama Abdelkader]

kvm_riscv_vcpu_pmu_snapshot_set_shmem() and kvm_riscv_vcpu_pmu_event_info()
returned -ENOMEM from the SBI extension handler, which caused 
kvm_riscv_vcpu_sbi_ecall() to abort KVM_RUN and surface the error to 
userspace instead of completing the ECALL with a negative SBI error in a0.
Use SBI_ERR_FAILURE and the normal retdata path, matching other PMU
handlers and kvm_sbi_ext_pmu_handler comment.

Signed-off-by: Osama Abdelkader <osama.abdelkader at gmail.com>
---
 arch/riscv/kvm/vcpu_pmu.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/kvm/vcpu_pmu.c b/arch/riscv/kvm/vcpu_pmu.c
index e873430e596b..f36b099f447c 100644
--- a/arch/riscv/kvm/vcpu_pmu.c
+++ b/arch/riscv/kvm/vcpu_pmu.c
@@ -435,8 +435,10 @@ int kvm_riscv_vcpu_pmu_snapshot_set_shmem(struct kvm_vcpu *vcpu, unsigned long s
 	}
 
 	kvpmu->sdata = kzalloc(snapshot_area_size, GFP_ATOMIC);
-	if (!kvpmu->sdata)
-		return -ENOMEM;
+	if (!kvpmu->sdata) {
+		sbiret = SBI_ERR_FAILURE;
+		goto out;
+	}
 
 	/* No need to check writable slot explicitly as kvm_vcpu_write_guest does it internally */
 	if (kvm_vcpu_write_guest(vcpu, saddr, kvpmu->sdata, snapshot_area_size)) {
@@ -480,8 +482,10 @@ int kvm_riscv_vcpu_pmu_event_info(struct kvm_vcpu *vcpu, unsigned long saddr_low
 	}
 
 	einfo = kzalloc(shmem_size, GFP_KERNEL);
-	if (!einfo)
-		return -ENOMEM;
+	if (!einfo) {
+		ret = SBI_ERR_FAILURE;
+		goto out;
+	}
 
 	ret = kvm_vcpu_read_guest(vcpu, shmem, einfo, shmem_size);
 	if (ret) {
-- 
2.43.0