diff mbox series

[09/17] hw/vfio/pci-quirks: Fix missing ERRP_GUARD() for error_prepend()

Message ID 20240229143914.1977550-10-zhao1.liu@linux.intel.com
State New
Headers show
Series Cleanup up to fix missing ERRP_GUARD() for error_prepend() | expand

Commit Message

Zhao Liu Feb. 29, 2024, 2:39 p.m. UTC 
From: Zhao Liu <zhao1.liu@intel.com>

As the comment in qapi/error, passing @errp to error_prepend() requires
ERRP_GUARD():

* = Why, when and how to use ERRP_GUARD() =
*
* Without ERRP_GUARD(), use of the @errp parameter is restricted:
...
* - It should not be passed to error_prepend(), error_vprepend() or
*   error_append_hint(), because that doesn't work with &error_fatal.
* ERRP_GUARD() lifts these restrictions.
*
* To use ERRP_GUARD(), add it right at the beginning of the function.
* @errp can then be used without worrying about the argument being
* NULL or &error_fatal.

ERRP_GUARD() could avoid the case when @errp is the pointer of
error_fatal, the user can't see this additional information, because
exit() happens in error_setg earlier than information is added [1].

In hw/vfio/pci-quirks.c, there're 2 functions passing @errp to
error_prepend() without ERRP_GUARD():
- vfio_add_nv_gpudirect_cap()
- vfio_add_vmd_shadow_cap()

Their @errp parameters are so widely sourced that it is necessary to
protect them with ERRP_GUARD().

To avoid the issue like [1] said, add missing ERRP_GUARD() at the
beginning of this function.

[1]: Issue description in the commit message of commit ae7c80a7bd73
     ("error: New macro ERRP_GUARD()").

Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: "Cédric Le Goater" <clg@redhat.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
---
 hw/vfio/pci-quirks.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Cédric Le Goater Feb. 29, 2024, 6:23 p.m. UTC | #1 
On 2/29/24 15:39, Zhao Liu wrote:
> From: Zhao Liu <zhao1.liu@intel.com>
> 
> As the comment in qapi/error, passing @errp to error_prepend() requires
> ERRP_GUARD():
> 
> * = Why, when and how to use ERRP_GUARD() =
> *
> * Without ERRP_GUARD(), use of the @errp parameter is restricted:
> ...
> * - It should not be passed to error_prepend(), error_vprepend() or
> *   error_append_hint(), because that doesn't work with &error_fatal.
> * ERRP_GUARD() lifts these restrictions.
> *
> * To use ERRP_GUARD(), add it right at the beginning of the function.
> * @errp can then be used without worrying about the argument being
> * NULL or &error_fatal.
> 
> ERRP_GUARD() could avoid the case when @errp is the pointer of
> error_fatal, the user can't see this additional information, because
> exit() happens in error_setg earlier than information is added [1].
> 
> In hw/vfio/pci-quirks.c, there're 2 functions passing @errp to
> error_prepend() without ERRP_GUARD():
> - vfio_add_nv_gpudirect_cap()
> - vfio_add_vmd_shadow_cap()
> 
> Their @errp parameters are so widely sourced that it is necessary to
> protect them with ERRP_GUARD().
> 
> To avoid the issue like [1] said, add missing ERRP_GUARD() at the
> beginning of this function.
> 
> [1]: Issue description in the commit message of commit ae7c80a7bd73
>       ("error: New macro ERRP_GUARD()").
> 
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Cc: "Cédric Le Goater" <clg@redhat.com>
> Signed-off-by: Zhao Liu <zhao1.liu@intel.com>


Reviewed-by: Cédric Le Goater <clg@redhat.com>

Thanks,

C.


> ---
>   hw/vfio/pci-quirks.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
> index 84b1a7b9485c..496fd1ee86bd 100644
> --- a/hw/vfio/pci-quirks.c
> +++ b/hw/vfio/pci-quirks.c
> @@ -1538,6 +1538,7 @@ static bool is_valid_std_cap_offset(uint8_t pos)
>   
>   static int vfio_add_nv_gpudirect_cap(VFIOPCIDevice *vdev, Error **errp)
>   {
> +    ERRP_GUARD();
>       PCIDevice *pdev = &vdev->pdev;
>       int ret, pos;
>       bool c8_conflict = false, d4_conflict = false;
> @@ -1630,6 +1631,7 @@ static int vfio_add_nv_gpudirect_cap(VFIOPCIDevice *vdev, Error **errp)
>   #define VMD_SHADOW_CAP_LEN 24
>   static int vfio_add_vmd_shadow_cap(VFIOPCIDevice *vdev, Error **errp)
>   {
> +    ERRP_GUARD();
>       uint8_t membar_phys[16];
>       int ret, pos = 0xE8;
>
diff mbox series

Patch

diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
index 84b1a7b9485c..496fd1ee86bd 100644
--- a/hw/vfio/pci-quirks.c
+++ b/hw/vfio/pci-quirks.c
@@ -1538,6 +1538,7 @@  static bool is_valid_std_cap_offset(uint8_t pos)
 
 static int vfio_add_nv_gpudirect_cap(VFIOPCIDevice *vdev, Error **errp)
 {
+    ERRP_GUARD();
     PCIDevice *pdev = &vdev->pdev;
     int ret, pos;
     bool c8_conflict = false, d4_conflict = false;
@@ -1630,6 +1631,7 @@  static int vfio_add_nv_gpudirect_cap(VFIOPCIDevice *vdev, Error **errp)
 #define VMD_SHADOW_CAP_LEN 24
 static int vfio_add_vmd_shadow_cap(VFIOPCIDevice *vdev, Error **errp)
 {
+    ERRP_GUARD();
     uint8_t membar_phys[16];
     int ret, pos = 0xE8;