Xen devel - Mar 2012 - [PATCH] xen: initialize platform_pci even if xen_emul_unplug=never

When xen_emul_unplug=never is specified on kernel command line
reading files from /sys/hypervisor is broken (returns -EBUSY).
It is caused by xen_bus dependency on platform_pci and
platform_pci isn''t initialized when xen_emul_unplug=never is
specified.

Fix it by allowing platform_pcii to ignore xen_emul_unplug=never,
and do not intialize xen_[blk|net]front instead.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 drivers/block/xen-blkfront.c |    3 +++
 drivers/net/xen-netfront.c   |    4 ++++
 drivers/xen/platform-pci.c   |    5 -----
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 2f22874..d5e1ab9 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1475,6 +1475,9 @@ static int __init xlblk_init(void)
 	if (!xen_domain())
 		return -ENODEV;
 
+	if (!xen_platform_pci_unplug)
+		return -ENODEV;
+
 	if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
 		printk(KERN_WARNING "xen_blk: can''t get major %d with name
%s\n",
 		       XENVBD_MAJOR, DEV_NAME);
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index b161750..663b32c 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -47,6 +47,7 @@
 #include <xen/xenbus.h>
 #include <xen/events.h>
 #include <xen/page.h>
+#include <xen/platform_pci.h>
 #include <xen/grant_table.h>
 
 #include <xen/interface/io/netif.h>
@@ -1964,6 +1965,9 @@ static int __init netif_init(void)
 	if (xen_initial_domain())
 		return 0;
 
+	if (!xen_platform_pci_unplug)
+		return -ENODEV;
+
 	printk(KERN_INFO "Initialising Xen virtual ethernet driver.\n");
 
 	return xenbus_register_frontend(&netfront_driver);
diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c
index 319dd0a..2389e58 100644
--- a/drivers/xen/platform-pci.c
+++ b/drivers/xen/platform-pci.c
@@ -186,11 +186,6 @@ static struct pci_driver platform_driver = {
 
 static int __init platform_pci_module_init(void)
 {
-	/* no unplug has been done, IGNORE hasn''t been specified: just
-	 * return now */
-	if (!xen_platform_pci_unplug)
-		return -ENODEV;
-
 	return pci_register_driver(&platform_driver);
 }
 
-- 
1.7.5

On Wed, 21 Mar 2012, Igor Mammedov wrote:
> When xen_emul_unplug=never is specified on kernel command line
> reading files from /sys/hypervisor is broken (returns -EBUSY).
> It is caused by xen_bus dependency on platform_pci and
> platform_pci isn''t initialized when xen_emul_unplug=never is
> specified.
> 
> Fix it by allowing platform_pcii to ignore xen_emul_unplug=never,
> and do not intialize xen_[blk|net]front instead.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

On Wed, Mar 21, 2012 at 03:08:38PM +0100, Igor Mammedov
wrote:
> When xen_emul_unplug=never is specified on kernel command line
> reading files from /sys/hypervisor is broken (returns -EBUSY).
> It is caused by xen_bus dependency on platform_pci and
> platform_pci isn''t initialized when xen_emul_unplug=never is
> specified.
Oh, good catch. Thx!
> 
> Fix it by allowing platform_pcii to ignore xen_emul_unplug=never,
> and do not intialize xen_[blk|net]front instead.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
>  drivers/block/xen-blkfront.c |    3 +++
>  drivers/net/xen-netfront.c   |    4 ++++
>  drivers/xen/platform-pci.c   |    5 -----
>  3 files changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> index 2f22874..d5e1ab9 100644
> --- a/drivers/block/xen-blkfront.c
> +++ b/drivers/block/xen-blkfront.c
> @@ -1475,6 +1475,9 @@ static int __init xlblk_init(void)
>  	if (!xen_domain())
>  		return -ENODEV;
>  
> +	if (!xen_platform_pci_unplug)
> +		return -ENODEV;
> +
>  	if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
>  		printk(KERN_WARNING "xen_blk: can''t get major %d with name
%s\n",
>  		       XENVBD_MAJOR, DEV_NAME);
> diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
> index b161750..663b32c 100644
> --- a/drivers/net/xen-netfront.c
> +++ b/drivers/net/xen-netfront.c
> @@ -47,6 +47,7 @@
>  #include <xen/xenbus.h>
>  #include <xen/events.h>
>  #include <xen/page.h>
> +#include <xen/platform_pci.h>
>  #include <xen/grant_table.h>
>  
>  #include <xen/interface/io/netif.h>
> @@ -1964,6 +1965,9 @@ static int __init netif_init(void)
>  	if (xen_initial_domain())
>  		return 0;
>  
> +	if (!xen_platform_pci_unplug)
> +		return -ENODEV;
> +
>  	printk(KERN_INFO "Initialising Xen virtual ethernet
driver.\n");
>  
>  	return xenbus_register_frontend(&netfront_driver);
> diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c
> index 319dd0a..2389e58 100644
> --- a/drivers/xen/platform-pci.c
> +++ b/drivers/xen/platform-pci.c
> @@ -186,11 +186,6 @@ static struct pci_driver platform_driver = {
>  
>  static int __init platform_pci_module_init(void)
>  {
> -	/* no unplug has been done, IGNORE hasn''t been specified: just
> -	 * return now */
> -	if (!xen_platform_pci_unplug)
> -		return -ENODEV;
> -
>  	return pci_register_driver(&platform_driver);
>  }
>  
> -- 
> 1.7.5
> 
> 
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