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[PATCH v3] virtio-pci: correctly set virtio pci queue mem multiplier

Srujana Challa posted 1 patch 9 months, 1 week ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20240223052617.1867132-1-schalla@marvell.com
Maintainers: "Michael S. Tsirkin" <mst@redhat.com>
There is a newer version of this series
hw/virtio/virtio-pci.c         | 10 ++++++++--
include/hw/virtio/virtio-pci.h |  5 +++++
2 files changed, 13 insertions(+), 2 deletions(-)
[PATCH v3] virtio-pci: correctly set virtio pci queue mem multiplier
Posted by Srujana Challa 9 months, 1 week ago 
Currently, virtio_pci_queue_mem_mult function always returns 4K
when VIRTIO_PCI_FLAG_PAGE_PER_VQ is set. But this won't
work for vhost vdpa when host has page size other than 4K.
This patch introduces a new property(host-page-per-vq) for vdpa
use case to fix the same.

Signed-off-by: Srujana Challa <schalla@marvell.com>
---
v2->v3:
- Modified property name, page-per-vdpa-vq to host-page-per-vq.

v1->v2:
- Introduced a new property to get virtqueue mem multiplier for
  vdpa use case.

 hw/virtio/virtio-pci.c         | 10 ++++++++--
 include/hw/virtio/virtio-pci.h |  5 +++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 1a7039fb0c..f29e60830b 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -320,8 +320,12 @@ static bool virtio_pci_ioeventfd_enabled(DeviceState *d)
 
 static inline int virtio_pci_queue_mem_mult(struct VirtIOPCIProxy *proxy)
 {
-    return (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ) ?
-        QEMU_VIRTIO_PCI_QUEUE_MEM_MULT : 4;
+    if (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ)
+        return QEMU_VIRTIO_PCI_QUEUE_MEM_MULT;
+    else if (proxy->flags & VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ)
+        return qemu_real_host_page_size();
+    else
+        return 4;
 }
 
 static int virtio_pci_ioeventfd_assign(DeviceState *d, EventNotifier *notifier,
@@ -2301,6 +2305,8 @@ static Property virtio_pci_properties[] = {
                     VIRTIO_PCI_FLAG_INIT_FLR_BIT, true),
     DEFINE_PROP_BIT("aer", VirtIOPCIProxy, flags,
                     VIRTIO_PCI_FLAG_AER_BIT, false),
+    DEFINE_PROP_BIT("host-page-per-vq", VirtIOPCIProxy, flags,
+                    VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT, false),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/virtio/virtio-pci.h b/include/hw/virtio/virtio-pci.h
index 59d88018c1..81b6de4291 100644
--- a/include/hw/virtio/virtio-pci.h
+++ b/include/hw/virtio/virtio-pci.h
@@ -43,6 +43,7 @@ enum {
     VIRTIO_PCI_FLAG_INIT_FLR_BIT,
     VIRTIO_PCI_FLAG_AER_BIT,
     VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT,
+    VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT,
 };
 
 /* Need to activate work-arounds for buggy guests at vmstate load. */
@@ -89,6 +90,10 @@ enum {
 #define VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED \
   (1 << VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT)
 
+/* page per vdpa vq flag to be used for vhost vdpa backends */
+#define VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ \
+    (1 << VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT)
+
 typedef struct {
     MSIMessage msg;
     int virq;
-- 
2.25.1
Re: [PATCH v3] virtio-pci: correctly set virtio pci queue mem multiplier
Posted by Michael S. Tsirkin 9 months, 1 week ago 
On Fri, Feb 23, 2024 at 10:56:17AM +0530, Srujana Challa wrote:
> Currently, virtio_pci_queue_mem_mult function always returns 4K
> when VIRTIO_PCI_FLAG_PAGE_PER_VQ is set. But this won't
> work for vhost vdpa when host has page size other than 4K.
> This patch introduces a new property(host-page-per-vq) for vdpa
> use case to fix the same.
> 
> Signed-off-by: Srujana Challa <schalla@marvell.com>

Looks good. I'd like to fail realize if both 
   (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ)
and
   (proxy->flags & VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ)
so users do not start depending on this combination.



> ---
> v2->v3:
> - Modified property name, page-per-vdpa-vq to host-page-per-vq.
> 
> v1->v2:
> - Introduced a new property to get virtqueue mem multiplier for
>   vdpa use case.
> 
>  hw/virtio/virtio-pci.c         | 10 ++++++++--
>  include/hw/virtio/virtio-pci.h |  5 +++++
>  2 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 1a7039fb0c..f29e60830b 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -320,8 +320,12 @@ static bool virtio_pci_ioeventfd_enabled(DeviceState *d)
>  
>  static inline int virtio_pci_queue_mem_mult(struct VirtIOPCIProxy *proxy)
>  {
> -    return (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ) ?
> -        QEMU_VIRTIO_PCI_QUEUE_MEM_MULT : 4;
> +    if (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ)
> +        return QEMU_VIRTIO_PCI_QUEUE_MEM_MULT;
> +    else if (proxy->flags & VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ)
> +        return qemu_real_host_page_size();
> +    else
> +        return 4;
>  }
>  
>  static int virtio_pci_ioeventfd_assign(DeviceState *d, EventNotifier *notifier,
> @@ -2301,6 +2305,8 @@ static Property virtio_pci_properties[] = {
>                      VIRTIO_PCI_FLAG_INIT_FLR_BIT, true),
>      DEFINE_PROP_BIT("aer", VirtIOPCIProxy, flags,
>                      VIRTIO_PCI_FLAG_AER_BIT, false),
> +    DEFINE_PROP_BIT("host-page-per-vq", VirtIOPCIProxy, flags,
> +                    VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT, false),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> diff --git a/include/hw/virtio/virtio-pci.h b/include/hw/virtio/virtio-pci.h
> index 59d88018c1..81b6de4291 100644
> --- a/include/hw/virtio/virtio-pci.h
> +++ b/include/hw/virtio/virtio-pci.h
> @@ -43,6 +43,7 @@ enum {
>      VIRTIO_PCI_FLAG_INIT_FLR_BIT,
>      VIRTIO_PCI_FLAG_AER_BIT,
>      VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT,
> +    VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT,
>  };
>  
>  /* Need to activate work-arounds for buggy guests at vmstate load. */
> @@ -89,6 +90,10 @@ enum {
>  #define VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED \
>    (1 << VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT)
>  
> +/* page per vdpa vq flag to be used for vhost vdpa backends */
> +#define VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ \
> +    (1 << VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT)
> +
>  typedef struct {
>      MSIMessage msg;
>      int virq;
> -- 
> 2.25.1
RE: [EXT] Re: [PATCH v3] virtio-pci: correctly set virtio pci queue mem multiplier
Posted by Srujana Challa 9 months ago 
> Subject: [EXT] Re: [PATCH v3] virtio-pci: correctly set virtio pci queue mem
> multiplier
> 
> External Email
> 
> ----------------------------------------------------------------------
> On Fri, Feb 23, 2024 at 10:56:17AM +0530, Srujana Challa wrote:
> > Currently, virtio_pci_queue_mem_mult function always returns 4K when
> > VIRTIO_PCI_FLAG_PAGE_PER_VQ is set. But this won't work for vhost vdpa
> > when host has page size other than 4K.
> > This patch introduces a new property(host-page-per-vq) for vdpa use
> > case to fix the same.
> >
> > Signed-off-by: Srujana Challa <schalla@marvell.com>
> 
> Looks good. I'd like to fail realize if both
>    (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ) and
>    (proxy->flags & VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ) so users do not
> start depending on this combination.
Could you confirm if we can add assertion for this case in virtio_pci_mem_mult() function?

> 
> 
> 
> > ---
> > v2->v3:
> > - Modified property name, page-per-vdpa-vq to host-page-per-vq.
> >
> > v1->v2:
> > - Introduced a new property to get virtqueue mem multiplier for
> >   vdpa use case.
> >
> >  hw/virtio/virtio-pci.c         | 10 ++++++++--
> >  include/hw/virtio/virtio-pci.h |  5 +++++
> >  2 files changed, 13 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index
> > 1a7039fb0c..f29e60830b 100644
> > --- a/hw/virtio/virtio-pci.c
> > +++ b/hw/virtio/virtio-pci.c
> > @@ -320,8 +320,12 @@ static bool
> > virtio_pci_ioeventfd_enabled(DeviceState *d)
> >
> >  static inline int virtio_pci_queue_mem_mult(struct VirtIOPCIProxy
> > *proxy)  {
> > -    return (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ) ?
> > -        QEMU_VIRTIO_PCI_QUEUE_MEM_MULT : 4;
> > +    if (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ)
> > +        return QEMU_VIRTIO_PCI_QUEUE_MEM_MULT;
> > +    else if (proxy->flags & VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ)
> > +        return qemu_real_host_page_size();
> > +    else
> > +        return 4;
> >  }
> >
> >  static int virtio_pci_ioeventfd_assign(DeviceState *d, EventNotifier
> > *notifier, @@ -2301,6 +2305,8 @@ static Property virtio_pci_properties[] =
> {
> >                      VIRTIO_PCI_FLAG_INIT_FLR_BIT, true),
> >      DEFINE_PROP_BIT("aer", VirtIOPCIProxy, flags,
> >                      VIRTIO_PCI_FLAG_AER_BIT, false),
> > +    DEFINE_PROP_BIT("host-page-per-vq", VirtIOPCIProxy, flags,
> > +                    VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT, false),
> >      DEFINE_PROP_END_OF_LIST(),
> >  };
> >
> > diff --git a/include/hw/virtio/virtio-pci.h
> > b/include/hw/virtio/virtio-pci.h index 59d88018c1..81b6de4291 100644
> > --- a/include/hw/virtio/virtio-pci.h
> > +++ b/include/hw/virtio/virtio-pci.h
> > @@ -43,6 +43,7 @@ enum {
> >      VIRTIO_PCI_FLAG_INIT_FLR_BIT,
> >      VIRTIO_PCI_FLAG_AER_BIT,
> >      VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT,
> > +    VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT,
> >  };
> >
> >  /* Need to activate work-arounds for buggy guests at vmstate load. */
> > @@ -89,6 +90,10 @@ enum {  #define
> VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED \
> >    (1 << VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT)
> >
> > +/* page per vdpa vq flag to be used for vhost vdpa backends */
> > +#define VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ \
> > +    (1 << VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT)
> > +
> >  typedef struct {
> >      MSIMessage msg;
> >      int virq;
> > --
> > 2.25.1
Re: [EXT] Re: [PATCH v3] virtio-pci: correctly set virtio pci queue mem multiplier
Posted by Michael S. Tsirkin 9 months ago 
On Wed, Feb 28, 2024 at 06:13:03AM +0000, Srujana Challa wrote:
> > Subject: [EXT] Re: [PATCH v3] virtio-pci: correctly set virtio pci queue mem
> > multiplier
> > 
> > External Email
> > 
> > ----------------------------------------------------------------------
> > On Fri, Feb 23, 2024 at 10:56:17AM +0530, Srujana Challa wrote:
> > > Currently, virtio_pci_queue_mem_mult function always returns 4K when
> > > VIRTIO_PCI_FLAG_PAGE_PER_VQ is set. But this won't work for vhost vdpa
> > > when host has page size other than 4K.
> > > This patch introduces a new property(host-page-per-vq) for vdpa use
> > > case to fix the same.
> > >
> > > Signed-off-by: Srujana Challa <schalla@marvell.com>
> > 
> > Looks good. I'd like to fail realize if both
> >    (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ) and
> >    (proxy->flags & VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ) so users do not
> > start depending on this combination.
> Could you confirm if we can add assertion for this case in virtio_pci_mem_mult() function?

No, reporting an error would be better since it's user-triggerable -
it is not nice to report user errors through assertions,
assertions are for conditions that can not be reached.


> > 
> > 
> > 
> > > ---
> > > v2->v3:
> > > - Modified property name, page-per-vdpa-vq to host-page-per-vq.
> > >
> > > v1->v2:
> > > - Introduced a new property to get virtqueue mem multiplier for
> > >   vdpa use case.
> > >
> > >  hw/virtio/virtio-pci.c         | 10 ++++++++--
> > >  include/hw/virtio/virtio-pci.h |  5 +++++
> > >  2 files changed, 13 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index
> > > 1a7039fb0c..f29e60830b 100644
> > > --- a/hw/virtio/virtio-pci.c
> > > +++ b/hw/virtio/virtio-pci.c
> > > @@ -320,8 +320,12 @@ static bool
> > > virtio_pci_ioeventfd_enabled(DeviceState *d)
> > >
> > >  static inline int virtio_pci_queue_mem_mult(struct VirtIOPCIProxy
> > > *proxy)  {
> > > -    return (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ) ?
> > > -        QEMU_VIRTIO_PCI_QUEUE_MEM_MULT : 4;
> > > +    if (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ)
> > > +        return QEMU_VIRTIO_PCI_QUEUE_MEM_MULT;
> > > +    else if (proxy->flags & VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ)
> > > +        return qemu_real_host_page_size();
> > > +    else
> > > +        return 4;
> > >  }
> > >
> > >  static int virtio_pci_ioeventfd_assign(DeviceState *d, EventNotifier
> > > *notifier, @@ -2301,6 +2305,8 @@ static Property virtio_pci_properties[] =
> > {
> > >                      VIRTIO_PCI_FLAG_INIT_FLR_BIT, true),
> > >      DEFINE_PROP_BIT("aer", VirtIOPCIProxy, flags,
> > >                      VIRTIO_PCI_FLAG_AER_BIT, false),
> > > +    DEFINE_PROP_BIT("host-page-per-vq", VirtIOPCIProxy, flags,
> > > +                    VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT, false),
> > >      DEFINE_PROP_END_OF_LIST(),
> > >  };
> > >
> > > diff --git a/include/hw/virtio/virtio-pci.h
> > > b/include/hw/virtio/virtio-pci.h index 59d88018c1..81b6de4291 100644
> > > --- a/include/hw/virtio/virtio-pci.h
> > > +++ b/include/hw/virtio/virtio-pci.h
> > > @@ -43,6 +43,7 @@ enum {
> > >      VIRTIO_PCI_FLAG_INIT_FLR_BIT,
> > >      VIRTIO_PCI_FLAG_AER_BIT,
> > >      VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT,
> > > +    VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT,
> > >  };
> > >
> > >  /* Need to activate work-arounds for buggy guests at vmstate load. */
> > > @@ -89,6 +90,10 @@ enum {  #define
> > VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED \
> > >    (1 << VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT)
> > >
> > > +/* page per vdpa vq flag to be used for vhost vdpa backends */
> > > +#define VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ \
> > > +    (1 << VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT)
> > > +
> > >  typedef struct {
> > >      MSIMessage msg;
> > >      int virq;
> > > --
> > > 2.25.1
RE: [EXT] Re: [PATCH v3] virtio-pci: correctly set virtio pci queue mem multiplier
Posted by Srujana Challa 9 months ago 
> Subject: Re: [EXT] Re: [PATCH v3] virtio-pci: correctly set virtio pci queue mem
> multiplier
> 
> On Wed, Feb 28, 2024 at 06:13:03AM +0000, Srujana Challa wrote:
> > > Subject: [EXT] Re: [PATCH v3] virtio-pci: correctly set virtio pci
> > > queue mem multiplier
> > >
> > > External Email
> > >
> > > --------------------------------------------------------------------
> > > -- On Fri, Feb 23, 2024 at 10:56:17AM +0530, Srujana Challa wrote:
> > > > Currently, virtio_pci_queue_mem_mult function always returns 4K
> > > > when VIRTIO_PCI_FLAG_PAGE_PER_VQ is set. But this won't work for
> > > > vhost vdpa when host has page size other than 4K.
> > > > This patch introduces a new property(host-page-per-vq) for vdpa
> > > > use case to fix the same.
> > > >
> > > > Signed-off-by: Srujana Challa <schalla@marvell.com>
> > >
> > > Looks good. I'd like to fail realize if both
> > >    (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ) and
> > >    (proxy->flags & VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ) so users do not
> > > start depending on this combination.
> > Could you confirm if we can add assertion for this case in
> virtio_pci_mem_mult() function?
> 
> No, reporting an error would be better since it's user-triggerable - it is not nice
> to report user errors through assertions, assertions are for conditions that can
> not be reached.
Yes, but returning error from virtio_pci_queue_mem_mult() would need changes
In multiple places right?

> 
> 
> > >
> > >
> > >
> > > > ---
> > > > v2->v3:
> > > > - Modified property name, page-per-vdpa-vq to host-page-per-vq.
> > > >
> > > > v1->v2:
> > > > - Introduced a new property to get virtqueue mem multiplier for
> > > >   vdpa use case.
> > > >
> > > >  hw/virtio/virtio-pci.c         | 10 ++++++++--
> > > >  include/hw/virtio/virtio-pci.h |  5 +++++
> > > >  2 files changed, 13 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index
> > > > 1a7039fb0c..f29e60830b 100644
> > > > --- a/hw/virtio/virtio-pci.c
> > > > +++ b/hw/virtio/virtio-pci.c
> > > > @@ -320,8 +320,12 @@ static bool
> > > > virtio_pci_ioeventfd_enabled(DeviceState *d)
> > > >
> > > >  static inline int virtio_pci_queue_mem_mult(struct VirtIOPCIProxy
> > > > *proxy)  {
> > > > -    return (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ) ?
> > > > -        QEMU_VIRTIO_PCI_QUEUE_MEM_MULT : 4;
> > > > +    if (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ)
> > > > +        return QEMU_VIRTIO_PCI_QUEUE_MEM_MULT;
> > > > +    else if (proxy->flags & VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ)
> > > > +        return qemu_real_host_page_size();
> > > > +    else
> > > > +        return 4;
> > > >  }
> > > >
> > > >  static int virtio_pci_ioeventfd_assign(DeviceState *d,
> > > > EventNotifier *notifier, @@ -2301,6 +2305,8 @@ static Property
> > > > virtio_pci_properties[] =
> > > {
> > > >                      VIRTIO_PCI_FLAG_INIT_FLR_BIT, true),
> > > >      DEFINE_PROP_BIT("aer", VirtIOPCIProxy, flags,
> > > >                      VIRTIO_PCI_FLAG_AER_BIT, false),
> > > > +    DEFINE_PROP_BIT("host-page-per-vq", VirtIOPCIProxy, flags,
> > > > +                    VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT, false),
> > > >      DEFINE_PROP_END_OF_LIST(),
> > > >  };
> > > >
> > > > diff --git a/include/hw/virtio/virtio-pci.h
> > > > b/include/hw/virtio/virtio-pci.h index 59d88018c1..81b6de4291
> > > > 100644
> > > > --- a/include/hw/virtio/virtio-pci.h
> > > > +++ b/include/hw/virtio/virtio-pci.h
> > > > @@ -43,6 +43,7 @@ enum {
> > > >      VIRTIO_PCI_FLAG_INIT_FLR_BIT,
> > > >      VIRTIO_PCI_FLAG_AER_BIT,
> > > >      VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT,
> > > > +    VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT,
> > > >  };
> > > >
> > > >  /* Need to activate work-arounds for buggy guests at vmstate
> > > > load. */ @@ -89,6 +90,10 @@ enum {  #define
> > > VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED \
> > > >    (1 << VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT)
> > > >
> > > > +/* page per vdpa vq flag to be used for vhost vdpa backends */
> > > > +#define VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ \
> > > > +    (1 << VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ_BIT)
> > > > +
> > > >  typedef struct {
> > > >      MSIMessage msg;
> > > >      int virq;
> > > > --
> > > > 2.25.1
Re: [PATCH v3] virtio-pci: correctly set virtio pci queue mem multiplier
Posted by Philippe Mathieu-Daudé 9 months, 1 week ago 
Hi Srujana,

On 23/2/24 06:26, Srujana Challa wrote:
> Currently, virtio_pci_queue_mem_mult function always returns 4K
> when VIRTIO_PCI_FLAG_PAGE_PER_VQ is set. But this won't
> work for vhost vdpa when host has page size other than 4K.
> This patch introduces a new property(host-page-per-vq) for vdpa
> use case to fix the same.
> 
> Signed-off-by: Srujana Challa <schalla@marvell.com>
> ---
> v2->v3:
> - Modified property name, page-per-vdpa-vq to host-page-per-vq.
> 
> v1->v2:
> - Introduced a new property to get virtqueue mem multiplier for
>    vdpa use case.
> 
>   hw/virtio/virtio-pci.c         | 10 ++++++++--
>   include/hw/virtio/virtio-pci.h |  5 +++++
>   2 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 1a7039fb0c..f29e60830b 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -320,8 +320,12 @@ static bool virtio_pci_ioeventfd_enabled(DeviceState *d)
>   
>   static inline int virtio_pci_queue_mem_mult(struct VirtIOPCIProxy *proxy)
>   {
> -    return (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ) ?
> -        QEMU_VIRTIO_PCI_QUEUE_MEM_MULT : 4;
> +    if (proxy->flags & VIRTIO_PCI_FLAG_PAGE_PER_VQ)
> +        return QEMU_VIRTIO_PCI_QUEUE_MEM_MULT;
> +    else if (proxy->flags & VIRTIO_PCI_FLAG_HOST_PAGE_PER_VQ)
> +        return qemu_real_host_page_size();
> +    else
> +        return 4;
 >   }

Per our coding style, this code should use braces:
https://www.qemu.org/docs/master/devel/style.html#block-structure

Regards,

Phil.

Patchew 2.1-devel-b67e4c2

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