accel/kvm: Check ioctl(KVM_SET_USER_MEMORY_REGION) return value

[PATCH] accel/kvm: Check ioctl(KVM_SET_USER_MEMORY_REGION) return value

Posted by Philippe Mathieu-Daudé 4 years, 2 months ago

kvm_vm_ioctl() can fail, check its return value, and log an error
when it failed. This fixes Coverity CID 1412229:

  Unchecked return value (CHECKED_RETURN)

  check_return: Calling kvm_vm_ioctl without checking return value

Reported-by: Coverity (CID 1412229)
Fixes: 235e8982ad3 ("support using KVM_MEM_READONLY flag for regions")
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 accel/kvm/kvm-all.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index c111312dfd..6df3a4d030 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -308,13 +308,23 @@ static int kvm_set_user_memory_region(KVMMemoryListener *kml, KVMSlot *slot, boo
         /* Set the slot size to 0 before setting the slot to the desired
          * value. This is needed based on KVM commit 75d61fbc. */
         mem.memory_size = 0;
-        kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
+        ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
+        if (ret < 0) {
+            goto err;
+        }
     }
     mem.memory_size = slot->memory_size;
     ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
     slot->old_flags = mem.flags;
+err:
     trace_kvm_set_user_memory(mem.slot, mem.flags, mem.guest_phys_addr,
                               mem.memory_size, mem.userspace_addr, ret);
+    if (ret < 0) {
+        error_report("%s: KVM_SET_USER_MEMORY_REGION failed, slot=%d,"
+                     " start=0x%" PRIx64 ", size=0x%" PRIx64 ": %s",
+                     __func__, mem.slot, slot->start_addr,
+                     (uint64_t)mem.memory_size, strerror(errno));
+    }
     return ret;
 }
 
-- 
2.21.1

Re: [PATCH] accel/kvm: Check ioctl(KVM_SET_USER_MEMORY_REGION) return value

Posted by Paolo Bonzini 4 years, 2 months ago

On 21/02/20 17:33, Philippe Mathieu-Daudé wrote:
> kvm_vm_ioctl() can fail, check its return value, and log an error
> when it failed. This fixes Coverity CID 1412229:
> 
>   Unchecked return value (CHECKED_RETURN)
> 
>   check_return: Calling kvm_vm_ioctl without checking return value
> 
> Reported-by: Coverity (CID 1412229)
> Fixes: 235e8982ad3 ("support using KVM_MEM_READONLY flag for regions")
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  accel/kvm/kvm-all.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index c111312dfd..6df3a4d030 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -308,13 +308,23 @@ static int kvm_set_user_memory_region(KVMMemoryListener *kml, KVMSlot *slot, boo
>          /* Set the slot size to 0 before setting the slot to the desired
>           * value. This is needed based on KVM commit 75d61fbc. */
>          mem.memory_size = 0;
> -        kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
> +        ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
> +        if (ret < 0) {
> +            goto err;
> +        }
>      }
>      mem.memory_size = slot->memory_size;
>      ret = kvm_vm_ioctl(s, KVM_SET_USER_MEMORY_REGION, &mem);
>      slot->old_flags = mem.flags;
> +err:
>      trace_kvm_set_user_memory(mem.slot, mem.flags, mem.guest_phys_addr,
>                                mem.memory_size, mem.userspace_addr, ret);
> +    if (ret < 0) {
> +        error_report("%s: KVM_SET_USER_MEMORY_REGION failed, slot=%d,"
> +                     " start=0x%" PRIx64 ", size=0x%" PRIx64 ": %s",
> +                     __func__, mem.slot, slot->start_addr,
> +                     (uint64_t)mem.memory_size, strerror(errno));
> +    }
>      return ret;
>  }
>  
> 

Queued, thanks.

Paolo

Re: [PATCH] accel/kvm: Check ioctl(KVM_SET_USER_MEMORY_REGION) return value

Posted by Peter Xu 4 years, 2 months ago

On Fri, Feb 21, 2020 at 05:33:36PM +0100, Philippe Mathieu-Daudé wrote:
> kvm_vm_ioctl() can fail, check its return value, and log an error
> when it failed. This fixes Coverity CID 1412229:
> 
>   Unchecked return value (CHECKED_RETURN)
> 
>   check_return: Calling kvm_vm_ioctl without checking return value
> 
> Reported-by: Coverity (CID 1412229)
> Fixes: 235e8982ad3 ("support using KVM_MEM_READONLY flag for regions")
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu