[Qemu-devel] [PULL 0/3] xen-20171026-tag

[Qemu-devel] [PULL 0/3] xen-20171026-tag

[Stefano Stabellini]

The following changes since commit 325a084c1ebccb265a3c8f1dd092ffbbfb448a00:

  Merge remote-tracking branch 'remotes/stefanberger/tags/pull-tpm-2017-10-24-1' into staging (2017-10-26 09:20:11 +0100)

are available in the git repository at:


  git://xenbits.xen.org/people/sstabellini/qemu-dm.git tags/xen-20171026-tag

for you to fetch changes up to 7cdcca725b6bfc96634c15e3f74ae4b148cf9c40:

  xen: Log errno rather than return value (2017-10-26 14:26:48 -0700)

----------------------------------------------------------------
Xen 2017/10/26

----------------------------------------------------------------
Juergen Gross (2):
      xen: add a global indicator for grant copy being available
      xen: dont try setting max grants multiple times

Ross Lagerwall (1):
      xen: Log errno rather than return value

 hw/block/xen_disk.c          | 34 ++++++++++++++++++----------------
 hw/i386/xen/xen-hvm.c        |  2 +-
 hw/xen/xen_backend.c         | 11 +++++++++++
 include/hw/xen/xen_backend.h |  1 +
 4 files changed, 31 insertions(+), 17 deletions(-)

[Qemu-devel] [PULL 1/3] xen: add a global indicator for grant copy being available

[Stefano Stabellini]

From: Juergen Gross <jgross@suse.com>

The Xen qdisk backend needs to test whether grant copy operations is
available in the kernel. Unfortunately this collides with using
xengnttab_set_max_grants() on some kernels as this operation has to
be the first one after opening the gnttab device.

In order to solve this problem test for the availability of grant copy
in xen_be_init() opening the gnttab device just for that purpose and
closing it again afterwards. Advertise the availability via a global
flag and use that flag in the qdisk backend.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
---
 hw/block/xen_disk.c          | 18 ++++++------------
 hw/xen/xen_backend.c         | 11 +++++++++++
 include/hw/xen/xen_backend.h |  1 +
 3 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
index 536e2ee..62506e3 100644
--- a/hw/block/xen_disk.c
+++ b/hw/block/xen_disk.c
@@ -121,9 +121,6 @@ struct XenBlkDev {
     unsigned int        persistent_gnt_count;
     unsigned int        max_grants;
 
-    /* Grant copy */
-    gboolean            feature_grant_copy;
-
     /* qemu block driver */
     DriveInfo           *dinfo;
     BlockBackend        *blk;
@@ -616,7 +613,7 @@ static void qemu_aio_complete(void *opaque, int ret)
         return;
     }
 
-    if (ioreq->blkdev->feature_grant_copy) {
+    if (xen_feature_grant_copy) {
         switch (ioreq->req.operation) {
         case BLKIF_OP_READ:
             /* in case of failure ioreq->aio_errors is increased */
@@ -638,7 +635,7 @@ static void qemu_aio_complete(void *opaque, int ret)
     }
 
     ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
-    if (!ioreq->blkdev->feature_grant_copy) {
+    if (!xen_feature_grant_copy) {
         ioreq_unmap(ioreq);
     }
     ioreq_finish(ioreq);
@@ -698,7 +695,7 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
 {
     struct XenBlkDev *blkdev = ioreq->blkdev;
 
-    if (ioreq->blkdev->feature_grant_copy) {
+    if (xen_feature_grant_copy) {
         ioreq_init_copy_buffers(ioreq);
         if (ioreq->req.nr_segments && (ioreq->req.operation == BLKIF_OP_WRITE ||
             ioreq->req.operation == BLKIF_OP_FLUSH_DISKCACHE) &&
@@ -750,7 +747,7 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
     }
     default:
         /* unknown operation (shouldn't happen -- parse catches this) */
-        if (!ioreq->blkdev->feature_grant_copy) {
+        if (!xen_feature_grant_copy) {
             ioreq_unmap(ioreq);
         }
         goto err;
@@ -1010,18 +1007,15 @@ static int blk_init(struct XenDevice *xendev)
 
     blkdev->file_blk  = BLOCK_SIZE;
 
-    blkdev->feature_grant_copy =
-                (xengnttab_grant_copy(blkdev->xendev.gnttabdev, 0, NULL) == 0);
-
     xen_pv_printf(&blkdev->xendev, 3, "grant copy operation %s\n",
-                  blkdev->feature_grant_copy ? "enabled" : "disabled");
+                  xen_feature_grant_copy ? "enabled" : "disabled");
 
     /* fill info
      * blk_connect supplies sector-size and sectors
      */
     xenstore_write_be_int(&blkdev->xendev, "feature-flush-cache", 1);
     xenstore_write_be_int(&blkdev->xendev, "feature-persistent",
-                          !blkdev->feature_grant_copy);
+                          !xen_feature_grant_copy);
     xenstore_write_be_int(&blkdev->xendev, "info", info);
 
     xenstore_write_be_int(&blkdev->xendev, "max-ring-page-order",
diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c
index c46cbb0..0f849a2 100644
--- a/hw/xen/xen_backend.c
+++ b/hw/xen/xen_backend.c
@@ -44,6 +44,7 @@ BusState *xen_sysbus;
 /* public */
 struct xs_handle *xenstore = NULL;
 const char *xen_protocol;
+bool xen_feature_grant_copy;
 
 /* private */
 static int debug;
@@ -519,6 +520,8 @@ void xenstore_update_fe(char *watch, struct XenDevice *xendev)
 
 int xen_be_init(void)
 {
+    xengnttab_handle *gnttabdev;
+
     xenstore = xs_daemon_open();
     if (!xenstore) {
         xen_pv_printf(NULL, 0, "can't connect to xenstored\n");
@@ -532,6 +535,14 @@ int xen_be_init(void)
         goto err;
     }
 
+    gnttabdev = xengnttab_open(NULL, 0);
+    if (gnttabdev != NULL) {
+        if (xengnttab_grant_copy(gnttabdev, 0, NULL) == 0) {
+            xen_feature_grant_copy = true;
+        }
+        xengnttab_close(gnttabdev);
+    }
+
     xen_sysdev = qdev_create(NULL, TYPE_XENSYSDEV);
     qdev_init_nofail(xen_sysdev);
     xen_sysbus = qbus_create(TYPE_XENSYSBUS, DEVICE(xen_sysdev), "xen-sysbus");
diff --git a/include/hw/xen/xen_backend.h b/include/hw/xen/xen_backend.h
index 8a6fbcb..3a27692 100644
--- a/include/hw/xen/xen_backend.h
+++ b/include/hw/xen/xen_backend.h
@@ -16,6 +16,7 @@
 /* variables */
 extern struct xs_handle *xenstore;
 extern const char *xen_protocol;
+extern bool xen_feature_grant_copy;
 extern DeviceState *xen_sysdev;
 extern BusState *xen_sysbus;
 
-- 
1.9.1

[Qemu-devel] [PULL 2/3] xen: dont try setting max grants multiple times

[Stefano Stabellini]

From: Juergen Gross <jgross@suse.com>

Trying to call xengnttab_set_max_grants() with the same file handle
might fail on some kernels, as this operation is allowed only once.

This is a problem for the qdisk backend as blk_connect() can be
called multiple times for a domain, e.g. in case grub-xen is being
used to boot it.

So instead of letting the generic backend code open the gnttab device
do it in blk_connect() and close it again in blk_disconnect.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
---
 hw/block/xen_disk.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
index 62506e3..e431bd8 100644
--- a/hw/block/xen_disk.c
+++ b/hw/block/xen_disk.c
@@ -1220,6 +1220,12 @@ static int blk_connect(struct XenDevice *xendev)
     /* Add on the number needed for the ring pages */
     max_grants += blkdev->nr_ring_ref;
 
+    blkdev->xendev.gnttabdev = xengnttab_open(NULL, 0);
+    if (blkdev->xendev.gnttabdev == NULL) {
+        xen_pv_printf(xendev, 0, "xengnttab_open failed: %s\n",
+                      strerror(errno));
+        return -1;
+    }
     if (xengnttab_set_max_grants(blkdev->xendev.gnttabdev, max_grants)) {
         xen_pv_printf(xendev, 0, "xengnttab_set_max_grants failed: %s\n",
                       strerror(errno));
@@ -1327,6 +1333,11 @@ static void blk_disconnect(struct XenDevice *xendev)
         }
         blkdev->feature_persistent = false;
     }
+
+    if (blkdev->xendev.gnttabdev) {
+        xengnttab_close(blkdev->xendev.gnttabdev);
+        blkdev->xendev.gnttabdev = NULL;
+    }
 }
 
 static int blk_free(struct XenDevice *xendev)
@@ -1334,9 +1345,7 @@ static int blk_free(struct XenDevice *xendev)
     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
     struct ioreq *ioreq;
 
-    if (blkdev->blk || blkdev->sring) {
-        blk_disconnect(xendev);
-    }
+    blk_disconnect(xendev);
 
     while (!QLIST_EMPTY(&blkdev->freelist)) {
         ioreq = QLIST_FIRST(&blkdev->freelist);
@@ -1363,7 +1372,6 @@ static void blk_event(struct XenDevice *xendev)
 
 struct XenDevOps xen_blkdev_ops = {
     .size       = sizeof(struct XenBlkDev),
-    .flags      = DEVOPS_FLAG_NEED_GNTDEV,
     .alloc      = blk_alloc,
     .init       = blk_init,
     .initialise    = blk_connect,
-- 
1.9.1

[Qemu-devel] [PULL 3/3] xen: Log errno rather than return value

[Stefano Stabellini]

From: Ross Lagerwall <ross.lagerwall@citrix.com>

xen_modified_memory() sets errno to communicate what went wrong so log
this rather than the return value which is not interesting.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
---
 hw/i386/xen/xen-hvm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
index d9ccd5d..8028bed 100644
--- a/hw/i386/xen/xen-hvm.c
+++ b/hw/i386/xen/xen-hvm.c
@@ -1446,7 +1446,7 @@ void xen_hvm_modified_memory(ram_addr_t start, ram_addr_t length)
         if (rc) {
             fprintf(stderr,
                     "%s failed for "RAM_ADDR_FMT" ("RAM_ADDR_FMT"): %i, %s\n",
-                    __func__, start, nb_pages, rc, strerror(-rc));
+                    __func__, start, nb_pages, errno, strerror(errno));
         }
     }
 }
-- 
1.9.1

Re: [Qemu-devel] [PULL 0/3] xen-20171026-tag

[Peter Maydell]

On 26 October 2017 at 23:59, Stefano Stabellini <sstabellini@kernel.org> wrote:
> The following changes since commit 325a084c1ebccb265a3c8f1dd092ffbbfb448a00:
>
>   Merge remote-tracking branch 'remotes/stefanberger/tags/pull-tpm-2017-10-24-1' into staging (2017-10-26 09:20:11 +0100)
>
> are available in the git repository at:
>
>
>   git://xenbits.xen.org/people/sstabellini/qemu-dm.git tags/xen-20171026-tag
>
> for you to fetch changes up to 7cdcca725b6bfc96634c15e3f74ae4b148cf9c40:
>
>   xen: Log errno rather than return value (2017-10-26 14:26:48 -0700)
>
> ----------------------------------------------------------------
> Xen 2017/10/26
>
> ----------------------------------------------------------------
> Juergen Gross (2):
>       xen: add a global indicator for grant copy being available
>       xen: dont try setting max grants multiple times
>
> Ross Lagerwall (1):
>       xen: Log errno rather than return value

Applied, thanks.

-- PMM