From: Juergen Gross <jgross@suse.com>
To: qemu-devel@nongnu.org, xen-devel@lists.xensource.com
Cc: anthony.perard@citrix.com, Juergen Gross <jgross@suse.com>,
sstabellini@kernel.org, kraxel@redhat.com
Subject: [PATCH] xen: use native disk xenbus protocol if possible
Date: Fri, 17 Jun 2016 13:14:56 +0200 [thread overview]
Message-ID: <1466162096-4934-1-git-send-email-jgross@suse.com> (raw)
The qdisk implementation is using the native xenbus protocol only in
case of no protocol specified at all. As using the explicit 32- or
64-bit protocol is slower than the native one due to copying requests
not by memcpy but element for element, this is not optimal.
Correct this by using the native protocol in case word sizes of
frontend and backend match.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
hw/block/xen_disk.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
index 2862b59..0961fcb 100644
--- a/hw/block/xen_disk.c
+++ b/hw/block/xen_disk.c
@@ -976,14 +976,14 @@ static int blk_connect(struct XenDevice *xendev)
blkdev->feature_persistent = !!pers;
}
- blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
- if (blkdev->xendev.protocol) {
- if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_32) == 0) {
- blkdev->protocol = BLKIF_PROTOCOL_X86_32;
- }
- if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_64) == 0) {
- blkdev->protocol = BLKIF_PROTOCOL_X86_64;
- }
+ if (!blkdev->xendev.protocol) {
+ blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
+ } else if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_NATIVE) == 0) {
+ blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
+ } else if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_32) == 0) {
+ blkdev->protocol = BLKIF_PROTOCOL_X86_32;
+ } else if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_64) == 0) {
+ blkdev->protocol = BLKIF_PROTOCOL_X86_64;
}
blkdev->sring = xengnttab_map_grant_ref(blkdev->xendev.gnttabdev,
--
2.6.6
next reply other threads:[~2016-06-17 11:14 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-17 11:14 Juergen Gross [this message]
2016-06-27 10:54 ` [Xen-devel] [PATCH] xen: use native disk xenbus protocol if possible Juergen Gross
2016-06-29 15:20 ` Anthony PERARD
2016-06-29 15:38 ` Juergen Gross
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