linux-stable.git/drivers/xen, branch v5.18.2

xen: Convert kmap() to kmap_local_page()

2022-04-20T20:22:18+00:00

kmap() is being deprecated and these usages are all local to the thread
so there is no reason kmap_local_page() can't be used.

Replace kmap() calls with kmap_local_page().

Signed-off-by: Alaa Mohamed 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/20220419234328.10346-1-eng.alaamohamedsoliman.am@gmail.com
Signed-off-by: Boris Ostrovsky

xen/balloon: don't use PV mode extra memory for zone device allocations

2022-04-07T20:08:37+00:00

When running as a Xen PV guest use the extra memory (memory which isn't
allocated for the guest at boot time) only for ballooning purposes and
not for zone device allocations. This will remove some code without any
lack of functionality.

While at it move some code to get rid of another #ifdef.

Remove a comment which is stale since some time now.

Signed-off-by: Juergen Gross 
Link: https://lore.kernel.org/r/20220407093857.1485-1-jgross@suse.com
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Boris Ostrovsky

xen: don't hang when resuming PCI device

2022-03-25T19:22:15+00:00

If a xen domain with at least two VCPUs has a PCI device attached which
enters the D3hot state during suspend, the kernel may hang while
resuming, depending on the core on which an async resume task gets
scheduled.

The bug occurs because xen's do_suspend calls dpm_resume_start while
only the timer of the boot CPU has been resumed (when xen_suspend called
syscore_resume), before calling xen_arch_suspend to resume the timers of
the other CPUs. This breaks pci_dev_d3_sleep.

Thus this patch moves the call to xen_arch_resume before the call to
dpm_resume_start, eliminating the hangs and restoring the stack-like
structure of the suspend/restore procedure.

Signed-off-by: Jakub Kądziołka 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/20220323012103.2537-1-niedzejkob@invisiblethingslab.com
Signed-off-by: Boris Ostrovsky

xen/grant-table: remove readonly parameter from functions

2022-03-16T01:34:40+00:00

The gnttab_end_foreign_access() family of functions is taking a
"readonly" parameter, which isn't used. Remove it from the function
parameters.

Signed-off-by: Juergen Gross 
Link: https://lore.kernel.org/r/20220311103429.12845-3-jgross@suse.com
Reviewed-by: Jan Beulich 
Acked-by: Christian Schoenebeck 
Signed-off-by: Boris Ostrovsky

xen/grant-table: remove gnttab_transfer() functions

2022-03-16T01:34:04+00:00

All grant table operations related to the "transfer" functionality
are unused currently. There have been users in the old days of the
"Xen-o-Linux" kernel, but those didn't make it upstream.

So remove the "transfer" related functions.

Signed-off-by: Juergen Gross 
Link: https://lore.kernel.org/r/20220311103429.12845-2-jgross@suse.com
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Boris Ostrovsky

drivers/xen: use helper macro __ATTR_RW

2022-03-10T15:27:55+00:00

Use helper macro __ATTR_RW to define HYPERVISOR_ATTR_RW to make code more clear.
Minor readability improvement.

Remove extra whitespace [boris: added this comment]

Signed-off-by: zhanglianjie 
Reviewed-by: Boris Ostrovsky 
Link: https://lore.kernel.org/r/20220305133823.158961-1-zhanglianjie@uniontech.com
Signed-off-by: Boris Ostrovsky

xen: use time_is_before_eq_jiffies() instead of open coding it

2022-03-10T15:27:55+00:00

Use the helper function time_is_{before,after}_jiffies() to improve
code readability.

Signed-off-by: Wang Qing 
Reviewed-by: Boris Ostrovsky 
Link: https://lore.kernel.org/r/1646018104-61415-1-git-send-email-wangqing@vivo.com
Signed-off-by: Boris Ostrovsky

xen/gnttab: fix gnttab_end_foreign_access() without page specified

2022-03-07T08:48:55+00:00

gnttab_end_foreign_access() is used to free a grant reference and
optionally to free the associated page. In case the grant is still in
use by the other side processing is being deferred. This leads to a
problem in case no page to be freed is specified by the caller: the
caller doesn't know that the page is still mapped by the other side
and thus should not be used for other purposes.

The correct way to handle this situation is to take an additional
reference to the granted page in case handling is being deferred and
to drop that reference when the grant reference could be freed
finally.

This requires that there are no users of gnttab_end_foreign_access()
left directly repurposing the granted page after the call, as this
might result in clobbered data or information leaks via the not yet
freed grant reference.

This is part of CVE-2022-23041 / XSA-396.

Reported-by: Simon Gaiser 
Signed-off-by: Juergen Gross 
Reviewed-by: Jan Beulich 
---
V4:
- expand comment in header
V5:
- get page ref in case of kmalloc() failure, too

xen/pvcalls: use alloc/free_pages_exact()