[PATCH] make vfio and DAX cache work together

[PATCH] make vfio and DAX cache work together

[Edge NFV]

I am using Kata containers and create containers inside the virtual machine. The hypervisor used is QEMU.
My workload is I/O and network intensive. So, I prefer SR-IOV VF (which provides better network isolation) and DAX caching to work together.
However, I was unable to create a QEMU based virual machine when the above mentioned featires are enabled together.

Currently DAX cache need to be set to 0, to boot the VM successfully with the SR-IOV VF to be attached.
Enabling both SR-IOV VF and DAX work together will potentially improve performance for workloads which are I/O and network intensive.
This patch enables SR-IOV VF and DAX to work together.

[PATCH] make vfio and DAX cache work together by skipping virtio fs cache section during vfio memory region add

[Edge NFV]

Signed-off-by: Edge NFV <edgenfv@gmail.com>
---
 hw/vfio/common.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index ae5654fcdb..83e15bf7a3 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -668,6 +668,15 @@ static void vfio_listener_region_add(MemoryListener *listener,
                 int128_get64(int128_sub(section->size, int128_one())));
         return;
     }
+    
+    /* Do not add virtio fs cache section */                  
+    if (!strcmp(memory_region_name(section->mr), "virtio-fs-cache")) {
+        trace_vfio_listener_region_add_skip(
+                section->offset_within_address_space,
+                section->offset_within_address_space +
+                int128_get64(int128_sub(section->size, int128_one())));
+        return;
+    }  
 
     if (unlikely((section->offset_within_address_space &
                   ~qemu_real_host_page_mask) !=
-- 
2.25.1

Re: [PATCH] make vfio and DAX cache work together by skipping virtio fs cache section during vfio memory region add

[no-reply]

Patchew URL: https://patchew.org/QEMU/20210426054513.132980-2-edgenfv@gmail.com/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Type: series
Message-id: 20210426054513.132980-2-edgenfv@gmail.com
Subject: [PATCH] make vfio and DAX cache work together by skipping virtio fs cache section during vfio memory region add

=== TEST SCRIPT BEGIN ===
#!/bin/bash
git rev-parse base > /dev/null || exit 0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
 * [new tag]         patchew/20210426054513.132980-2-edgenfv@gmail.com -> patchew/20210426054513.132980-2-edgenfv@gmail.com
Switched to a new branch 'test'
32bddb3 make vfio and DAX cache work together by skipping virtio fs cache section during vfio memory region add

=== OUTPUT BEGIN ===
ERROR: trailing whitespace
#21: FILE: hw/vfio/common.c:671:
+    $

ERROR: trailing whitespace
#22: FILE: hw/vfio/common.c:672:
+    /* Do not add virtio fs cache section */                  $

ERROR: trailing whitespace
#29: FILE: hw/vfio/common.c:679:
+    }  $

total: 3 errors, 0 warnings, 15 lines checked

Commit 32bddb3c2253 (make vfio and DAX cache work together by skipping virtio fs cache section during vfio memory region add) has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/20210426054513.132980-2-edgenfv@gmail.com/testing.checkpatch/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-devel@redhat.com

Re: [PATCH] make vfio and DAX cache work together by skipping virtio fs cache section during vfio memory region add

[Laurent Vivier]

On 26/04/2021 07:45, Edge NFV wrote:
> Signed-off-by: Edge NFV <edgenfv@gmail.com>

You must use your real name for a patch submission:

https://wiki.qemu.org/Contribute/SubmitAPatch#Patch_emails_must_include_a_Signed-off-by:_line

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/SubmittingPatches?id=f6f94e2ab1b33f0082ac22d71f66385a60d8157f#n297

And CC: maintainer of the file:

$ ./scripts/get_maintainer.pl -f hw/vfio/common.c
Alex Williamson <alex.williamson@redhat.com> (supporter:VFIO)
qemu-devel@nongnu.org (open list:All patches CC here)

If you want to submit it to qemu-trivial, don't send a separate mail, but cc: also
qemu-trivial.

Thanks,
Laurent

> ---
>  hw/vfio/common.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index ae5654fcdb..83e15bf7a3 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -668,6 +668,15 @@ static void vfio_listener_region_add(MemoryListener *listener,
>                  int128_get64(int128_sub(section->size, int128_one())));
>          return;
>      }
> +    
> +    /* Do not add virtio fs cache section */                  
> +    if (!strcmp(memory_region_name(section->mr), "virtio-fs-cache")) {
> +        trace_vfio_listener_region_add_skip(
> +                section->offset_within_address_space,
> +                section->offset_within_address_space +
> +                int128_get64(int128_sub(section->size, int128_one())));
> +        return;
> +    }  
>  
>      if (unlikely((section->offset_within_address_space &
>                    ~qemu_real_host_page_mask) !=
>