From: Konrad Rzeszutek Wilk <hidden> Date: 2013-12-03 21:44:50
The user has the option of disabling the platform driver:
00:02.0 Unassigned class [ff80]: XenSource, Inc. Xen Platform Device (rev 01)
which is used to unplug the emulated drivers (IDE, Realtek 8169, etc)
and allow the PV drivers to take over. If the user wishes
to disable that they can set:
xen_platform_pci=0
(in the guest config file)
or
xen_emul_unplug=never
(on the Linux command line)
except it does not work properly. The PV drivers still try to
load and since the Xen platform driver is not run - and it
has not initialized the grant tables, most of the PV drivers
stumble upon:
input: Xen Virtual Keyboard as /devices/virtual/input/input5
input: Xen Virtual Pointer as /devices/virtual/input/input6M
------------[ cut here ]------------
kernel BUG at /home/konrad/ssd/konrad/linux/drivers/xen/grant-table.c:1206!
invalid opcode: 0000 [#1] SMP
Modules linked in: xen_kbdfront(+) xenfs xen_privcmd
CPU: 6 PID: 1389 Comm: modprobe Not tainted 3.13.0-rc1upstream-00021-ga6c892b-dirty #1
Hardware name: Xen HVM domU, BIOS 4.4-unstable 11/26/2013
RIP: 0010:[<ffffffff813ddc40>] [<ffffffff813ddc40>] get_free_entries+0x2e0/0x300
Call Trace:
[<ffffffff8150d9a3>] ? evdev_connect+0x1e3/0x240
[<ffffffff813ddd0e>] gnttab_grant_foreign_access+0x2e/0x70
[<ffffffffa0010081>] xenkbd_connect_backend+0x41/0x290 [xen_kbdfront]
[<ffffffffa0010a12>] xenkbd_probe+0x2f2/0x324 [xen_kbdfront]
[<ffffffff813e5757>] xenbus_dev_probe+0x77/0x130
[<ffffffff813e7217>] xenbus_frontend_dev_probe+0x47/0x50
[<ffffffff8145e9a9>] driver_probe_device+0x89/0x230
[<ffffffff8145ebeb>] __driver_attach+0x9b/0xa0
[<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230
[<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230
[<ffffffff8145cf1c>] bus_for_each_dev+0x8c/0xb0
[<ffffffff8145e7d9>] driver_attach+0x19/0x20
[<ffffffff8145e260>] bus_add_driver+0x1a0/0x220
[<ffffffff8145f1ff>] driver_register+0x5f/0xf0
[<ffffffff813e55c5>] xenbus_register_driver_common+0x15/0x20
[<ffffffff813e76b3>] xenbus_register_frontend+0x23/0x40
[<ffffffffa0015000>] ? 0xffffffffa0014fff
[<ffffffffa001502b>] xenkbd_init+0x2b/0x1000 [xen_kbdfront]
[<ffffffff81002049>] do_one_initcall+0x49/0x170
.. snip..
which is hardly nice. This patch fixes this by having each
PV driver check for:
- if running in PV, then it is fine to execute (as that is their
native environment).
- if running in HVM, check if user wanted 'xen_emul_unplug=never',
in which case bail out and don't load PV drivers.
- if running in HVM, and if PCI device 5853:0001 (xen_platform_pci)
does not exist, then bail out and not load PV drivers.
P.S.
Ian Campbell suggested getting rid of 'xen_platform_pci_unplug'
but unfortunatly the xen-blkfront driver is using it, so we
cannot do it.
Reported-by: Sander Eikelenboom <linux@eikelenboom.it
Reported-by: Anthony PERARD <redacted>
Reported-by: Fabio Fantoni <redacted>
---
arch/x86/xen/platform-pci-unplug.c | 18 ++++++++++++++++++
drivers/block/xen-blkfront.c | 2 +-
drivers/char/tpm/xen-tpmfront.c | 4 ++++
drivers/input/misc/xen-kbdfront.c | 4 ++++
drivers/net/xen-netfront.c | 2 +-
drivers/pci/xen-pcifront.c | 4 ++++
drivers/video/xen-fbfront.c | 4 ++++
drivers/xen/xenbus/xenbus_probe_frontend.c | 2 +-
include/xen/platform_pci.h | 13 ++++++++++++-
9 files changed, 49 insertions(+), 4 deletions(-)
@@ -69,6 +69,24 @@ static int check_platform_magic(void)return0;}+boolxen_has_pv_devices(void)+{+if(!xen_domain())+returnfalse;++if(xen_hvm_domain()){+/* User requested no unplug, so no PV drivers. */+if(xen_emul_unplug&XEN_UNPLUG_NEVER)+returnfalse;+/* And user has xen_platform_pci=0 set in guest config as+*driverdidnotmodifythevalue.*/+if(!xen_platform_pci_unplug)+returnfalse;+}+returntrue;+}+EXPORT_SYMBOL_GPL(xen_has_pv_devices);+voidxen_unplug_emulated_devices(void){intr;
From: Matthew Daley <hidden> Date: 2013-12-04 00:03:41
On Wed, Dec 4, 2013 at 10:14 AM, Konrad Rzeszutek Wilk
[off-list ref] wrote:
The user has the option of disabling the platform driver:
00:02.0 Unassigned class [ff80]: XenSource, Inc. Xen Platform Device (rev 01)
which is used to unplug the emulated drivers (IDE, Realtek 8169, etc)
and allow the PV drivers to take over. If the user wishes
to disable that they can set:
xen_platform_pci=0
(in the guest config file)
or
xen_emul_unplug=never
(on the Linux command line)
except it does not work properly. The PV drivers still try to
load and since the Xen platform driver is not run - and it
has not initialized the grant tables, most of the PV drivers
stumble upon:
input: Xen Virtual Keyboard as /devices/virtual/input/input5
input: Xen Virtual Pointer as /devices/virtual/input/input6M
------------[ cut here ]------------
kernel BUG at /home/konrad/ssd/konrad/linux/drivers/xen/grant-table.c:1206!
invalid opcode: 0000 [#1] SMP
Modules linked in: xen_kbdfront(+) xenfs xen_privcmd
CPU: 6 PID: 1389 Comm: modprobe Not tainted 3.13.0-rc1upstream-00021-ga6c892b-dirty #1
Hardware name: Xen HVM domU, BIOS 4.4-unstable 11/26/2013
RIP: 0010:[<ffffffff813ddc40>] [<ffffffff813ddc40>] get_free_entries+0x2e0/0x300
Call Trace:
[<ffffffff8150d9a3>] ? evdev_connect+0x1e3/0x240
[<ffffffff813ddd0e>] gnttab_grant_foreign_access+0x2e/0x70
[<ffffffffa0010081>] xenkbd_connect_backend+0x41/0x290 [xen_kbdfront]
[<ffffffffa0010a12>] xenkbd_probe+0x2f2/0x324 [xen_kbdfront]
[<ffffffff813e5757>] xenbus_dev_probe+0x77/0x130
[<ffffffff813e7217>] xenbus_frontend_dev_probe+0x47/0x50
[<ffffffff8145e9a9>] driver_probe_device+0x89/0x230
[<ffffffff8145ebeb>] __driver_attach+0x9b/0xa0
[<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230
[<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230
[<ffffffff8145cf1c>] bus_for_each_dev+0x8c/0xb0
[<ffffffff8145e7d9>] driver_attach+0x19/0x20
[<ffffffff8145e260>] bus_add_driver+0x1a0/0x220
[<ffffffff8145f1ff>] driver_register+0x5f/0xf0
[<ffffffff813e55c5>] xenbus_register_driver_common+0x15/0x20
[<ffffffff813e76b3>] xenbus_register_frontend+0x23/0x40
[<ffffffffa0015000>] ? 0xffffffffa0014fff
[<ffffffffa001502b>] xenkbd_init+0x2b/0x1000 [xen_kbdfront]
[<ffffffff81002049>] do_one_initcall+0x49/0x170
.. snip..
which is hardly nice. This patch fixes this by having each
PV driver check for:
- if running in PV, then it is fine to execute (as that is their
native environment).
- if running in HVM, check if user wanted 'xen_emul_unplug=never',
in which case bail out and don't load PV drivers.
- if running in HVM, and if PCI device 5853:0001 (xen_platform_pci)
does not exist, then bail out and not load PV drivers.
P.S.
Ian Campbell suggested getting rid of 'xen_platform_pci_unplug'
but unfortunatly the xen-blkfront driver is using it, so we
cannot do it.
Reported-by: Sander Eikelenboom <linux@eikelenboom.it
Reported-by: Anthony PERARD <redacted>
Reported-by: Fabio Fantoni <redacted>
I think you forgot your Signed-off-by line.
- Matthew
From: Ian Campbell <hidden> Date: 2013-12-04 09:37:40
On Tue, 2013-12-03 at 16:14 -0500, Konrad Rzeszutek Wilk wrote:
The user has the option of disabling the platform driver:
00:02.0 Unassigned class [ff80]: XenSource, Inc. Xen Platform Device (rev 01)
which is used to unplug the emulated drivers (IDE, Realtek 8169, etc)
and allow the PV drivers to take over. If the user wishes
to disable that they can set:
xen_platform_pci=0
(in the guest config file)
or
xen_emul_unplug=never
(on the Linux command line)
except it does not work properly. The PV drivers still try to
load and since the Xen platform driver is not run - and it
has not initialized the grant tables, most of the PV drivers
stumble upon:
input: Xen Virtual Keyboard as /devices/virtual/input/input5
input: Xen Virtual Pointer as /devices/virtual/input/input6M
------------[ cut here ]------------
kernel BUG at /home/konrad/ssd/konrad/linux/drivers/xen/grant-table.c:1206!
invalid opcode: 0000 [#1] SMP
Modules linked in: xen_kbdfront(+) xenfs xen_privcmd
CPU: 6 PID: 1389 Comm: modprobe Not tainted 3.13.0-rc1upstream-00021-ga6c892b-dirty #1
Hardware name: Xen HVM domU, BIOS 4.4-unstable 11/26/2013
RIP: 0010:[<ffffffff813ddc40>] [<ffffffff813ddc40>] get_free_entries+0x2e0/0x300
Call Trace:
[<ffffffff8150d9a3>] ? evdev_connect+0x1e3/0x240
[<ffffffff813ddd0e>] gnttab_grant_foreign_access+0x2e/0x70
[<ffffffffa0010081>] xenkbd_connect_backend+0x41/0x290 [xen_kbdfront]
[<ffffffffa0010a12>] xenkbd_probe+0x2f2/0x324 [xen_kbdfront]
[<ffffffff813e5757>] xenbus_dev_probe+0x77/0x130
[<ffffffff813e7217>] xenbus_frontend_dev_probe+0x47/0x50
[<ffffffff8145e9a9>] driver_probe_device+0x89/0x230
[<ffffffff8145ebeb>] __driver_attach+0x9b/0xa0
[<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230
[<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230
[<ffffffff8145cf1c>] bus_for_each_dev+0x8c/0xb0
[<ffffffff8145e7d9>] driver_attach+0x19/0x20
[<ffffffff8145e260>] bus_add_driver+0x1a0/0x220
[<ffffffff8145f1ff>] driver_register+0x5f/0xf0
[<ffffffff813e55c5>] xenbus_register_driver_common+0x15/0x20
[<ffffffff813e76b3>] xenbus_register_frontend+0x23/0x40
[<ffffffffa0015000>] ? 0xffffffffa0014fff
[<ffffffffa001502b>] xenkbd_init+0x2b/0x1000 [xen_kbdfront]
[<ffffffff81002049>] do_one_initcall+0x49/0x170
.. snip..
which is hardly nice. This patch fixes this by having each
PV driver check for:
- if running in PV, then it is fine to execute (as that is their
native environment).
- if running in HVM, check if user wanted 'xen_emul_unplug=never',
in which case bail out and don't load PV drivers.
- if running in HVM, and if PCI device 5853:0001 (xen_platform_pci)
does not exist, then bail out and not load PV drivers.
P.S.
Ian Campbell suggested getting rid of 'xen_platform_pci_unplug'
but unfortunatly the xen-blkfront driver is using it, so we
cannot do it.
It might still be nice to expose a suitable semantic interface (i.e.
some relevant predicate) rather than the raw value for blkfront to use.
But that can be a future thing I think.
@@ -69,6 +69,24 @@ static int check_platform_magic(void)return0;}+boolxen_has_pv_devices(void)+{+if(!xen_domain())+returnfalse;++if(xen_hvm_domain()){+/* User requested no unplug, so no PV drivers. */+if(xen_emul_unplug&XEN_UNPLUG_NEVER)+returnfalse;
I think you need
if (xen_emul_unpug & XEN_UNPLUG_UNNECESSARY)
return true;
don't you?
+ /* And user has xen_platform_pci=0 set in guest config as
+ * driver did not modify the value. */
+ if (!xen_platform_pci_unplug)
+ return false;
+ }
+ return true;
+}
+EXPORT_SYMBOL_GPL(xen_has_pv_devices);
+
void xen_unplug_emulated_devices(void)
{
int r;
@@ -69,6 +69,24 @@ static int check_platform_magic(void)return0;}+boolxen_has_pv_devices(void)+{+if(!xen_domain())+returnfalse;++if(xen_hvm_domain()){+/* User requested no unplug, so no PV drivers. */+if(xen_emul_unplug&XEN_UNPLUG_NEVER)+returnfalse;
Considering that if (xen_emul_unplug & XEN_UNPLUG_NEVER) we never set
xen_platform_pci_unplug, this check is redundant.
+ /* And user has xen_platform_pci=0 set in guest config as
+ * driver did not modify the value. */
+ if (!xen_platform_pci_unplug)
+ return false;
+ }
+ return true;
+}
+EXPORT_SYMBOL_GPL(xen_has_pv_devices);
+
void xen_unplug_emulated_devices(void)
{
int r;
+bool xen_has_pv_devices(void)
+{
+ if (!xen_domain())
+ return false;
+
+ if (xen_hvm_domain()) {
+ /* User requested no unplug, so no PV drivers. */
+ if (xen_emul_unplug & XEN_UNPLUG_NEVER)
+ return false;
I think you need
if (xen_emul_unpug & XEN_UNPLUG_UNNECESSARY)
return true;
don't you?
XEN_UNPLUG_UNNECESSARY was introduced to enable the platform PCI device
even if it didn't respond properly to the unplug protocol.
The corresponding parameter is called "unnecessary" because if you pass
it to the kernel you mean that it is unnecessary to unplug the emulated
devices but you can use the pv devices anyway.
So no, we shouldn't check for XEN_UNPLUG_UNNECESSARY here.
quoted
+ /* And user has xen_platform_pci=0 set in guest config as
+ * driver did not modify the value. */
+ if (!xen_platform_pci_unplug)
+ return false;
+ }
+ return true;
+}
+EXPORT_SYMBOL_GPL(xen_has_pv_devices);
+
void xen_unplug_emulated_devices(void)
{
int r;
From: Ian Campbell <hidden> Date: 2013-12-04 10:59:50
On Wed, 2013-12-04 at 10:51 +0000, Stefano Stabellini wrote:
On Wed, 4 Dec 2013, Ian Campbell wrote:
quoted
quoted
+bool xen_has_pv_devices(void)
+{
+ if (!xen_domain())
+ return false;
+
+ if (xen_hvm_domain()) {
+ /* User requested no unplug, so no PV drivers. */
+ if (xen_emul_unplug & XEN_UNPLUG_NEVER)
+ return false;
I think you need
if (xen_emul_unpug & XEN_UNPLUG_UNNECESSARY)
return true;
don't you?
XEN_UNPLUG_UNNECESSARY was introduced to enable the platform PCI device
even if it didn't respond properly to the unplug protocol.
The corresponding parameter is called "unnecessary" because if you pass
it to the kernel you mean that it is unnecessary to unplug the emulated
devices but you can use the pv devices anyway.
So no, we shouldn't check for XEN_UNPLUG_UNNECESSARY here.
Oh, we will eventually fall through to the return true, so it does
actually work out OK.
I'd still be in favour of handling each option explicitly, for clarity.
Which means checking for XEN_UNPLUG_UNNECESSARY.
quoted
quoted
+ /* And user has xen_platform_pci=0 set in guest config as
+ * driver did not modify the value. */
+ if (!xen_platform_pci_unplug)
+ return false;
I assume this check doesn't trigger if unnecessary has been specified?
On Wed, 2013-12-04 at 10:51 +0000, Stefano Stabellini wrote:
quoted
On Wed, 4 Dec 2013, Ian Campbell wrote:
quoted
quoted
+bool xen_has_pv_devices(void)
+{
+ if (!xen_domain())
+ return false;
+
+ if (xen_hvm_domain()) {
+ /* User requested no unplug, so no PV drivers. */
+ if (xen_emul_unplug & XEN_UNPLUG_NEVER)
+ return false;
I think you need
if (xen_emul_unpug & XEN_UNPLUG_UNNECESSARY)
return true;
don't you?
XEN_UNPLUG_UNNECESSARY was introduced to enable the platform PCI device
even if it didn't respond properly to the unplug protocol.
The corresponding parameter is called "unnecessary" because if you pass
it to the kernel you mean that it is unnecessary to unplug the emulated
devices but you can use the pv devices anyway.
So no, we shouldn't check for XEN_UNPLUG_UNNECESSARY here.
Oh, we will eventually fall through to the return true, so it does
actually work out OK.
I'd still be in favour of handling each option explicitly, for clarity.
Which means checking for XEN_UNPLUG_UNNECESSARY.
I think is wrong to check for any xen_emul_unpug options in this function.
The xen_emul_unpug options should be used to set the right value of
xen_platform_pci_unplug. (See my other reply.)
quoted
quoted
quoted
+ /* And user has xen_platform_pci=0 set in guest config as
+ * driver did not modify the value. */
+ if (!xen_platform_pci_unplug)
+ return false;
I assume this check doesn't trigger if unnecessary has been specified?
From: Ian Campbell <hidden> Date: 2013-12-04 11:08:18
On Wed, 2013-12-04 at 11:05 +0000, Stefano Stabellini wrote:
On Wed, 4 Dec 2013, Ian Campbell wrote:
quoted
On Wed, 2013-12-04 at 10:51 +0000, Stefano Stabellini wrote:
quoted
On Wed, 4 Dec 2013, Ian Campbell wrote:
quoted
quoted
+bool xen_has_pv_devices(void)
+{
+ if (!xen_domain())
+ return false;
+
+ if (xen_hvm_domain()) {
+ /* User requested no unplug, so no PV drivers. */
+ if (xen_emul_unplug & XEN_UNPLUG_NEVER)
+ return false;
I think you need
if (xen_emul_unpug & XEN_UNPLUG_UNNECESSARY)
return true;
don't you?
XEN_UNPLUG_UNNECESSARY was introduced to enable the platform PCI device
even if it didn't respond properly to the unplug protocol.
The corresponding parameter is called "unnecessary" because if you pass
it to the kernel you mean that it is unnecessary to unplug the emulated
devices but you can use the pv devices anyway.
So no, we shouldn't check for XEN_UNPLUG_UNNECESSARY here.
Oh, we will eventually fall through to the return true, so it does
actually work out OK.
I'd still be in favour of handling each option explicitly, for clarity.
Which means checking for XEN_UNPLUG_UNNECESSARY.
I think is wrong to check for any xen_emul_unpug options in this function.
The xen_emul_unpug options should be used to set the right value of
xen_platform_pci_unplug. (See my other reply.)
Whichever one we check we should still be checking explicitly for the
"unnecessary" case, for clarity if nothing else.
TBH I think the split between xen_emul_unplug and
xen_platform_pci_unplug is a bit artificial. There should be one value
which is static to platform-pci-unplug.c and accessor functions should
be provided for other code to use. Open coding all those accesses to
xen_platform_pci_unplug in every driver is just too error prone.
Ian.
On Wed, 2013-12-04 at 11:05 +0000, Stefano Stabellini wrote:
quoted
On Wed, 4 Dec 2013, Ian Campbell wrote:
quoted
On Wed, 2013-12-04 at 10:51 +0000, Stefano Stabellini wrote:
quoted
On Wed, 4 Dec 2013, Ian Campbell wrote:
quoted
quoted
+bool xen_has_pv_devices(void)
+{
+ if (!xen_domain())
+ return false;
+
+ if (xen_hvm_domain()) {
+ /* User requested no unplug, so no PV drivers. */
+ if (xen_emul_unplug & XEN_UNPLUG_NEVER)
+ return false;
I think you need
if (xen_emul_unpug & XEN_UNPLUG_UNNECESSARY)
return true;
don't you?
XEN_UNPLUG_UNNECESSARY was introduced to enable the platform PCI device
even if it didn't respond properly to the unplug protocol.
The corresponding parameter is called "unnecessary" because if you pass
it to the kernel you mean that it is unnecessary to unplug the emulated
devices but you can use the pv devices anyway.
So no, we shouldn't check for XEN_UNPLUG_UNNECESSARY here.
Oh, we will eventually fall through to the return true, so it does
actually work out OK.
I'd still be in favour of handling each option explicitly, for clarity.
Which means checking for XEN_UNPLUG_UNNECESSARY.
I think is wrong to check for any xen_emul_unpug options in this function.
The xen_emul_unpug options should be used to set the right value of
xen_platform_pci_unplug. (See my other reply.)
Whichever one we check we should still be checking explicitly for the
"unnecessary" case, for clarity if nothing else.
Sure, that is OK for me.
In that case should we check for the full list of possible options?
ide-disks -- unplug primary master IDE devices
aux-ide-disks -- unplug non-primary-master IDE devices
nics -- unplug network devices
all -- unplug all emulated devices (NICs and IDE disks)
unnecessary -- unplugging emulated devices is
unnecessary even if the host did not respond to
the unplug protocol
never -- do not unplug even if version check succeeds
From: Ian Campbell <hidden> Date: 2013-12-04 11:23:47
On Wed, 2013-12-04 at 11:18 +0000, Stefano Stabellini wrote:
On Wed, 4 Dec 2013, Ian Campbell wrote:
quoted
On Wed, 2013-12-04 at 11:05 +0000, Stefano Stabellini wrote:
quoted
On Wed, 4 Dec 2013, Ian Campbell wrote:
quoted
On Wed, 2013-12-04 at 10:51 +0000, Stefano Stabellini wrote:
quoted
On Wed, 4 Dec 2013, Ian Campbell wrote:
quoted
quoted
+bool xen_has_pv_devices(void)
+{
+ if (!xen_domain())
+ return false;
+
+ if (xen_hvm_domain()) {
+ /* User requested no unplug, so no PV drivers. */
+ if (xen_emul_unplug & XEN_UNPLUG_NEVER)
+ return false;
I think you need
if (xen_emul_unpug & XEN_UNPLUG_UNNECESSARY)
return true;
don't you?
XEN_UNPLUG_UNNECESSARY was introduced to enable the platform PCI device
even if it didn't respond properly to the unplug protocol.
The corresponding parameter is called "unnecessary" because if you pass
it to the kernel you mean that it is unnecessary to unplug the emulated
devices but you can use the pv devices anyway.
So no, we shouldn't check for XEN_UNPLUG_UNNECESSARY here.
Oh, we will eventually fall through to the return true, so it does
actually work out OK.
I'd still be in favour of handling each option explicitly, for clarity.
Which means checking for XEN_UNPLUG_UNNECESSARY.
I think is wrong to check for any xen_emul_unpug options in this function.
The xen_emul_unpug options should be used to set the right value of
xen_platform_pci_unplug. (See my other reply.)
Whichever one we check we should still be checking explicitly for the
"unnecessary" case, for clarity if nothing else.
Sure, that is OK for me.
In that case should we check for the full list of possible options?
We probably should. That probably means an extra
xen_has_pv_{disk,nic}_devices() which is the existing one plus the
specific checks?
ide-disks -- unplug primary master IDE devices
aux-ide-disks -- unplug non-primary-master IDE devices
nics -- unplug network devices
all -- unplug all emulated devices (NICs and IDE disks)
unnecessary -- unplugging emulated devices is
unnecessary even if the host did not respond to
the unplug protocol
never -- do not unplug even if version check succeeds
From: David Vrabel <hidden> Date: 2013-12-04 13:00:16
On 03/12/13 21:14, Konrad Rzeszutek Wilk wrote:
Ian Campbell suggested getting rid of 'xen_platform_pci_unplug'
but unfortunatly the xen-blkfront driver is using it, so we
cannot do it.
I had a look at what blkfront was using this for and it seems dumb. How
did we end up with the frontend driver working around toolstack bugs?
If HVM Linux guest didn't want (e.g.,) PV CDROM, the toolstack shouldn't
have created one.
And perhaps more importantly, if you actually want a PV CDROM in a HVM
guest, it's not possible.
David
From: Ian Campbell <hidden> Date: 2013-12-04 13:06:43
On Wed, 2013-12-04 at 13:00 +0000, David Vrabel wrote:
On 03/12/13 21:14, Konrad Rzeszutek Wilk wrote:
quoted
Ian Campbell suggested getting rid of 'xen_platform_pci_unplug'
but unfortunatly the xen-blkfront driver is using it, so we
cannot do it.
I had a look at what blkfront was using this for and it seems dumb. How
did we end up with the frontend driver working around toolstack bugs?
If HVM Linux guest didn't want (e.g.,) PV CDROM, the toolstack shouldn't
have created one.
Note that this cdrom stuff is actually nothing to do with the unplug
variable -- it just happens to be right next to that check.
Not that the use of the unplug var there doesn't also look pretty odd...
Hi Konrad,
On Tue, Dec 03, 2013 at 04:14:06PM -0500, Konrad Rzeszutek Wilk wrote:
The user has the option of disabling the platform driver:
00:02.0 Unassigned class [ff80]: XenSource, Inc. Xen Platform Device (rev 01)
which is used to unplug the emulated drivers (IDE, Realtek 8169, etc)
and allow the PV drivers to take over. If the user wishes
to disable that they can set:
xen_platform_pci=0
(in the guest config file)
or
xen_emul_unplug=never
(on the Linux command line)
except it does not work properly. The PV drivers still try to
load and since the Xen platform driver is not run - and it
has not initialized the grant tables, most of the PV drivers
stumble upon:
input: Xen Virtual Keyboard as /devices/virtual/input/input5
input: Xen Virtual Pointer as /devices/virtual/input/input6M
------------[ cut here ]------------
kernel BUG at /home/konrad/ssd/konrad/linux/drivers/xen/grant-table.c:1206!
invalid opcode: 0000 [#1] SMP
Modules linked in: xen_kbdfront(+) xenfs xen_privcmd
CPU: 6 PID: 1389 Comm: modprobe Not tainted 3.13.0-rc1upstream-00021-ga6c892b-dirty #1
Hardware name: Xen HVM domU, BIOS 4.4-unstable 11/26/2013
RIP: 0010:[<ffffffff813ddc40>] [<ffffffff813ddc40>] get_free_entries+0x2e0/0x300
Call Trace:
[<ffffffff8150d9a3>] ? evdev_connect+0x1e3/0x240
[<ffffffff813ddd0e>] gnttab_grant_foreign_access+0x2e/0x70
[<ffffffffa0010081>] xenkbd_connect_backend+0x41/0x290 [xen_kbdfront]
[<ffffffffa0010a12>] xenkbd_probe+0x2f2/0x324 [xen_kbdfront]
[<ffffffff813e5757>] xenbus_dev_probe+0x77/0x130
[<ffffffff813e7217>] xenbus_frontend_dev_probe+0x47/0x50
[<ffffffff8145e9a9>] driver_probe_device+0x89/0x230
[<ffffffff8145ebeb>] __driver_attach+0x9b/0xa0
[<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230
[<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230
[<ffffffff8145cf1c>] bus_for_each_dev+0x8c/0xb0
[<ffffffff8145e7d9>] driver_attach+0x19/0x20
[<ffffffff8145e260>] bus_add_driver+0x1a0/0x220
[<ffffffff8145f1ff>] driver_register+0x5f/0xf0
[<ffffffff813e55c5>] xenbus_register_driver_common+0x15/0x20
[<ffffffff813e76b3>] xenbus_register_frontend+0x23/0x40
[<ffffffffa0015000>] ? 0xffffffffa0014fff
[<ffffffffa001502b>] xenkbd_init+0x2b/0x1000 [xen_kbdfront]
[<ffffffff81002049>] do_one_initcall+0x49/0x170
.. snip..
which is hardly nice. This patch fixes this by having each
PV driver check for:
- if running in PV, then it is fine to execute (as that is their
native environment).
- if running in HVM, check if user wanted 'xen_emul_unplug=never',
in which case bail out and don't load PV drivers.
- if running in HVM, and if PCI device 5853:0001 (xen_platform_pci)
does not exist, then bail out and not load PV drivers.
P.S.
Ian Campbell suggested getting rid of 'xen_platform_pci_unplug'
but unfortunatly the xen-blkfront driver is using it, so we
cannot do it.
Reported-by: Sander Eikelenboom <linux@eikelenboom.it
Reported-by: Anthony PERARD <redacted>
Reported-by: Fabio Fantoni <redacted>
For input:
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
...
From: Konrad Rzeszutek Wilk <hidden> Date: 2013-12-04 16:49:48
quoted
which is hardly nice. This patch fixes this by having each
PV driver check for:
- if running in PV, then it is fine to execute (as that is their
native environment).
- if running in HVM, check if user wanted 'xen_emul_unplug=never',
in which case bail out and don't load PV drivers.
- if running in HVM, and if PCI device 5853:0001 (xen_platform_pci)
does not exist, then bail out and not load PV drivers.
P.S.
Ian Campbell suggested getting rid of 'xen_platform_pci_unplug'
but unfortunatly the xen-blkfront driver is using it, so we
cannot do it.
Reported-by: Sander Eikelenboom <linux@eikelenboom.it
Reported-by: Anthony PERARD <redacted>
Reported-by: Fabio Fantoni <redacted>
For input:
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Thank you. I need to do some extra changes to the other subsystems but
for the fb/kbd itshould be still throught the same function as this
patch has exposed. I will repost it and include your Ack if you are OK
with that?
On Wed, Dec 04, 2013 at 11:48:03AM -0500, Konrad Rzeszutek Wilk wrote:
quoted
quoted
which is hardly nice. This patch fixes this by having each
PV driver check for:
- if running in PV, then it is fine to execute (as that is their
native environment).
- if running in HVM, check if user wanted 'xen_emul_unplug=never',
in which case bail out and don't load PV drivers.
- if running in HVM, and if PCI device 5853:0001 (xen_platform_pci)
does not exist, then bail out and not load PV drivers.
P.S.
Ian Campbell suggested getting rid of 'xen_platform_pci_unplug'
but unfortunatly the xen-blkfront driver is using it, so we
cannot do it.
Reported-by: Sander Eikelenboom <linux@eikelenboom.it
Reported-by: Anthony PERARD <redacted>
Reported-by: Fabio Fantoni <redacted>
For input:
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Thank you. I need to do some extra changes to the other subsystems but
for the fb/kbd itshould be still throught the same function as this
patch has exposed. I will repost it and include your Ack if you are OK
with that?