[PATCH v1 0/1] xen: Remove invalidation of mapcache_grants on IOREQ_TYPE_INVALIDATE

[PATCH v1 0/1] xen: Remove invalidation of mapcache_grants on IOREQ_TYPE_INVALIDATE

[Edgar E. Iglesias]

From: "Edgar E. Iglesias" <edgar.iglesias@amd.com>

Olaf reported a slowdown in boot time on x86 HVM guests and Stefano
provided a patch that removes the invalidation of the grants mapcache
since not needed, more details here:
https://lore.kernel.org/all/Z5oIvUINVDfrrVla@zapote/T/

Cheers,
Edgar

Stefano Stabellini (1):
  xen: No need to flush the mapcache for grants

 hw/xen/xen-mapcache.c | 1 -
 1 file changed, 1 deletion(-)

-- 
2.43.0

[PATCH v1 1/1] xen: No need to flush the mapcache for grants

[Edgar E. Iglesias]

From: Stefano Stabellini <stefano.stabellini@amd.com>

On IOREQ_TYPE_INVALIDATE we need to invalidate the mapcache for regular
mappings. Since recently we started reusing the mapcache also to keep
track of grants mappings. However, there is no need to remove grant
mappings on IOREQ_TYPE_INVALIDATE requests, we shouldn't do that. So
remove the function call.

Fixes: 9ecdd4bf08 (xen: mapcache: Add support for grant mappings)
Cc: qemu-stable@nongnu.org
Reported-by: Olaf Hering <olaf@aepfle.de>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
---
 hw/xen/xen-mapcache.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/hw/xen/xen-mapcache.c b/hw/xen/xen-mapcache.c
index 00bfbcc6fb..698b5c53ed 100644
--- a/hw/xen/xen-mapcache.c
+++ b/hw/xen/xen-mapcache.c
@@ -700,7 +700,6 @@ void xen_invalidate_map_cache(void)
     bdrv_drain_all();
 
     xen_invalidate_map_cache_single(mapcache);
-    xen_invalidate_map_cache_single(mapcache_grants);
 }
 
 static uint8_t *xen_replace_cache_entry_unlocked(MapCache *mc,
-- 
2.43.0

Re: [PATCH v1 1/1] xen: No need to flush the mapcache for grants

[Anthony PERARD]

On Thu, Feb 06, 2025 at 08:49:15PM +0100, Edgar E. Iglesias wrote:
> From: Stefano Stabellini <stefano.stabellini@amd.com>
> 
> On IOREQ_TYPE_INVALIDATE we need to invalidate the mapcache for regular
> mappings. Since recently we started reusing the mapcache also to keep
> track of grants mappings. However, there is no need to remove grant
> mappings on IOREQ_TYPE_INVALIDATE requests, we shouldn't do that. So
> remove the function call.
> 
> Fixes: 9ecdd4bf08 (xen: mapcache: Add support for grant mappings)
> Cc: qemu-stable@nongnu.org
> Reported-by: Olaf Hering <olaf@aepfle.de>
> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@amd.com>

Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>

Thanks,

-- 
Anthony PERARD