[PATCH 0/2] vfio-user: trivial VFIOProxy flags fix

[PATCH 0/2] vfio-user: trivial VFIOProxy flags fix

[Mark Cave-Ayland]

This series contains a couple of trivial fixes for the VFIOProxy flags
found whilst rebasing some internal patches.

The first patch in the series fixes the incorrect value of the
VFIO_PROXY_USE_MULTI constant, whilst the second patch updates the
constants to use the BIT() macro (also removing a gap in the bit
numbering) to help prevent similar errors from occurring in future.

Note that the VFIOProxy flags are internal to QEMU and not included in
the migration stream so there are no visible effects from the bit
renumbering.

Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>

Mark Cave-Ayland (2):
  vfio-user: fix VFIO_PROXY_USE_MULTI constant value
  vfio-user: update VFIOProxy flag constants to use the BIT() macro

 hw/vfio-user/proxy.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

-- 
2.43.0

[PATCH 1/2] vfio-user: fix VFIO_PROXY_USE_MULTI constant value

[Mark Cave-Ayland]

The constant value should represent the next bit in the VFIOProxy flags which
is 0x10 and not 0x16.

Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
---
 hw/vfio-user/proxy.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/vfio-user/proxy.h b/hw/vfio-user/proxy.h
index 61e64a0020..b09fd886f1 100644
--- a/hw/vfio-user/proxy.h
+++ b/hw/vfio-user/proxy.h
@@ -94,7 +94,7 @@ typedef struct VFIOUserProxy {
 #define VFIO_PROXY_CLIENT        0x1
 #define VFIO_PROXY_FORCE_QUEUED  0x4
 #define VFIO_PROXY_NO_POST       0x8
-#define VFIO_PROXY_USE_MULTI     0x16
+#define VFIO_PROXY_USE_MULTI     0x10
 
 /* coalescing high and low water marks for VFIOProxy num_outgoing */
 #define VFIO_USER_OUT_HIGH       1024
-- 
2.43.0

Re: [PATCH 1/2] vfio-user: fix VFIO_PROXY_USE_MULTI constant value

[John Levon]

On Wed, Jan 21, 2026 at 10:59:45AM +0000, Mark Cave-Ayland wrote:

> The constant value should represent the next bit in the VFIOProxy flags which
> is 0x10 and not 0x16.
> 
> Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
> ---
>  hw/vfio-user/proxy.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/vfio-user/proxy.h b/hw/vfio-user/proxy.h
> index 61e64a0020..b09fd886f1 100644
> --- a/hw/vfio-user/proxy.h
> +++ b/hw/vfio-user/proxy.h
> @@ -94,7 +94,7 @@ typedef struct VFIOUserProxy {
>  #define VFIO_PROXY_CLIENT        0x1
>  #define VFIO_PROXY_FORCE_QUEUED  0x4
>  #define VFIO_PROXY_NO_POST       0x8
> -#define VFIO_PROXY_USE_MULTI     0x16
> +#define VFIO_PROXY_USE_MULTI     0x10
>  
>  /* coalescing high and low water marks for VFIOProxy num_outgoing */
>  #define VFIO_USER_OUT_HIGH       1024

Reviewed-by: John Levon <john.levon@nutanix.com>

thanks
john

Re: [PATCH 1/2] vfio-user: fix VFIO_PROXY_USE_MULTI constant value

[Cédric Le Goater]

On 1/21/26 11:59, Mark Cave-Ayland wrote:
> The constant value should represent the next bit in the VFIOProxy flags which
> is 0x10 and not 0x16.
> 
> Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>

Should there be a Fixes tag ?

Thanks,

C.


> ---
>   hw/vfio-user/proxy.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/vfio-user/proxy.h b/hw/vfio-user/proxy.h
> index 61e64a0020..b09fd886f1 100644
> --- a/hw/vfio-user/proxy.h
> +++ b/hw/vfio-user/proxy.h
> @@ -94,7 +94,7 @@ typedef struct VFIOUserProxy {
>   #define VFIO_PROXY_CLIENT        0x1
>   #define VFIO_PROXY_FORCE_QUEUED  0x4
>   #define VFIO_PROXY_NO_POST       0x8
> -#define VFIO_PROXY_USE_MULTI     0x16
> +#define VFIO_PROXY_USE_MULTI     0x10
>   
>   /* coalescing high and low water marks for VFIOProxy num_outgoing */
>   #define VFIO_USER_OUT_HIGH       1024

Re: [PATCH 1/2] vfio-user: fix VFIO_PROXY_USE_MULTI constant value

[Mark Cave-Ayland]

On 21/01/2026 11:15, Cédric Le Goater wrote:

> On 1/21/26 11:59, Mark Cave-Ayland wrote:
>> The constant value should represent the next bit in the VFIOProxy 
>> flags which
>> is 0x10 and not 0x16.
>>
>> Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
> 
> Should there be a Fixes tag ?

Yes indeed, it should be:

Fixes: 1a0c32a9da ("vfio-user: add coalesced posted writes")

Would you like me to resend a v2?


ATB,

Mark.

> Thanks,
> 
> C.
> 
> 
>> ---
>>   hw/vfio-user/proxy.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/hw/vfio-user/proxy.h b/hw/vfio-user/proxy.h
>> index 61e64a0020..b09fd886f1 100644
>> --- a/hw/vfio-user/proxy.h
>> +++ b/hw/vfio-user/proxy.h
>> @@ -94,7 +94,7 @@ typedef struct VFIOUserProxy {
>>   #define VFIO_PROXY_CLIENT        0x1
>>   #define VFIO_PROXY_FORCE_QUEUED  0x4
>>   #define VFIO_PROXY_NO_POST       0x8
>> -#define VFIO_PROXY_USE_MULTI     0x16
>> +#define VFIO_PROXY_USE_MULTI     0x10
>>   /* coalescing high and low water marks for VFIOProxy num_outgoing */
>>   #define VFIO_USER_OUT_HIGH       1024

Re: [PATCH 1/2] vfio-user: fix VFIO_PROXY_USE_MULTI constant value

[John Levon]

On Wed, Jan 21, 2026 at 10:59:45AM +0000, Mark Cave-Ayland wrote:

> The constant value should represent the next bit in the VFIOProxy flags which
> is 0x10 and not 0x16.
> 
> Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
> ---
>  hw/vfio-user/proxy.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/vfio-user/proxy.h b/hw/vfio-user/proxy.h
> index 61e64a0020..b09fd886f1 100644
> --- a/hw/vfio-user/proxy.h
> +++ b/hw/vfio-user/proxy.h
> @@ -94,7 +94,7 @@ typedef struct VFIOUserProxy {
>  #define VFIO_PROXY_CLIENT        0x1
>  #define VFIO_PROXY_FORCE_QUEUED  0x4
>  #define VFIO_PROXY_NO_POST       0x8
> -#define VFIO_PROXY_USE_MULTI     0x16
> +#define VFIO_PROXY_USE_MULTI     0x10
>  
>  /* coalescing high and low water marks for VFIOProxy num_outgoing */
>  #define VFIO_USER_OUT_HIGH       1024

In case anyone is wondering, this never bit us because the MULTI support is not
yet merged into libvfio-user

regards
john

[PATCH 2/2] vfio-user: update VFIOProxy flag constants to use the BIT() macro

[Mark Cave-Ayland]

This should help avoid incorrect constant values being used in future. At
the same time we can remove the gap left for BIT(1) which was originally
intended for the VFIO_PROXY_NO_MMAP feature which was removed from later
versions of the vfio-user series.

Suggested-by: John Levon <john.levon@nutanix.com>
Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
---
 hw/vfio-user/proxy.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/vfio-user/proxy.h b/hw/vfio-user/proxy.h
index b09fd886f1..7b97460cc5 100644
--- a/hw/vfio-user/proxy.h
+++ b/hw/vfio-user/proxy.h
@@ -91,10 +91,10 @@ typedef struct VFIOUserProxy {
 } VFIOUserProxy;
 
 /* VFIOProxy flags */
-#define VFIO_PROXY_CLIENT        0x1
-#define VFIO_PROXY_FORCE_QUEUED  0x4
-#define VFIO_PROXY_NO_POST       0x8
-#define VFIO_PROXY_USE_MULTI     0x10
+#define VFIO_PROXY_CLIENT        BIT(0)
+#define VFIO_PROXY_FORCE_QUEUED  BIT(1)
+#define VFIO_PROXY_NO_POST       BIT(2)
+#define VFIO_PROXY_USE_MULTI     BIT(3)
 
 /* coalescing high and low water marks for VFIOProxy num_outgoing */
 #define VFIO_USER_OUT_HIGH       1024
-- 
2.43.0

Re: [PATCH 2/2] vfio-user: update VFIOProxy flag constants to use the BIT() macro

[John Levon]

On Wed, Jan 21, 2026 at 10:59:46AM +0000, Mark Cave-Ayland wrote:

> This should help avoid incorrect constant values being used in future. At
> the same time we can remove the gap left for BIT(1) which was originally
> intended for the VFIO_PROXY_NO_MMAP feature which was removed from later
> versions of the vfio-user series.
> 
> Suggested-by: John Levon <john.levon@nutanix.com>
> Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
> ---
>  hw/vfio-user/proxy.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/vfio-user/proxy.h b/hw/vfio-user/proxy.h
> index b09fd886f1..7b97460cc5 100644
> --- a/hw/vfio-user/proxy.h
> +++ b/hw/vfio-user/proxy.h
> @@ -91,10 +91,10 @@ typedef struct VFIOUserProxy {
>  } VFIOUserProxy;
>  
>  /* VFIOProxy flags */
> -#define VFIO_PROXY_CLIENT        0x1
> -#define VFIO_PROXY_FORCE_QUEUED  0x4
> -#define VFIO_PROXY_NO_POST       0x8
> -#define VFIO_PROXY_USE_MULTI     0x10
> +#define VFIO_PROXY_CLIENT        BIT(0)
> +#define VFIO_PROXY_FORCE_QUEUED  BIT(1)
> +#define VFIO_PROXY_NO_POST       BIT(2)
> +#define VFIO_PROXY_USE_MULTI     BIT(3)
>  
>  /* coalescing high and low water marks for VFIOProxy num_outgoing */
>  #define VFIO_USER_OUT_HIGH       1024

Reviewed-by: John Levon <john.levon@nutanix.com>

thanks
john