xen/unlz4: always set an error return code on failures

"ret", being set to -1 early on, gets cleared by the first invocation
of lz4_decompress()/lz4_decompress_unknownoutputsize(), and hence
subsequent failures wouldn't be noticed by the caller without setting
it back to -1 right after those calls.

Linux commit: 2a1d689c9ba42a6066540fb221b6ecbd6298b728

Reported-by: Matthew Daley <mattjd@gmail.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
blkif.h: enhance comments related to the discard feature

Also fix the name of the discard-alignment property, add the missing 'n'.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Keir Fraser <keir@xen.org>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Update QEMU_UPSTREAM_REVISION

Switch back to master.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Update QEMU_TAG and QEMU_UPSTREAM_REVISION for 4.4.0-rc3

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Update QEMU_TAG and QEMU_UPSTREAM_REVISION for 4.4.0-rc3

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
(cherry picked from commit a96bbe5fd79ea8ac6b40e90965f84aab839d3391)
Merge branch 'master' into staging
QEMU_UPSTREAM_REVISION -> master again
x86/domctl: don't ignore errors from vmce_restore_vcpu()

What started out as a simple cleanup patch (eliminating the redundant
check of domctl->cmd before setting "copyback", which as a result
turned the "ext_vcpucontext_out" label useless) revealed a bug in the
handling of XEN_DOMCTL_set_ext_vcpucontext.

Fix this, retaining the cleanup, and at once dropping a stale comment
and an accompanying formatting issue.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
tools/libxc: goto correct label on error paths

Both of these "goto finish;" statements are actually errors, and need to "goto
out;" instead, which will correctly destroy the domain and return an error,
rather than trying to finish the migration (and in at least one scenario,
return success).

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: George Dunlap <george.dunlap@eu.citrix.com>
doc: Better documentation about the usbdevice=['host:bus.addr'] format

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
[ ijc -- minor wording tweak ]
xl: update check-xl-disk-parse to handle backend_domname

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
libxc: fix claim mode when creating HVM guest

The original code is wrong because:
* claim mode wants to know the total number of pages needed while
  original code provides the additional number of pages needed.
* if pod is enabled memory will already be allocated by the time we try
  to claim memory.

So the fix would be:
* move claim mode before actual memory allocation.
* pass the right number of pages to hypervisor.

The "right number of pages" should be number of pages of target memory
minus VGA_HOLE_SIZE, regardless of whether PoD is enabled.

This fixes bug #32.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
xen/arm: Directly return NULL if Xen fails to allocate domain struct

The current implementation of alloc_domain_struct, dereference the newly
allocated pointer even if the allocation has failed.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
xen: arm: correct use of find_next_bit

find_next_bit takes a "const unsigned long *" but forcing a cast of an
"uint32_t *" throws away the alignment constraints and ends up causing an
alignment fault on arm64 if the input happened to be 4 but not 8 byte aligned.

Instead of casting use a temporary variable of the right type.

I've had a look around for similar constructs and the only thing I found was
maintenance_interrupt which cases a uint64_t down to an unsigned long, which
although perhaps not best advised is safe I think.

This was observed with the AArch64 Linaro toolchain 2013.12 but I think that
is just coincidental due to subtle changes to the stack layout etc.

Reported-by: Fu Wei <fu.wei@linaro.org>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Julien Grall <julien.grall@linaro.org>
tools: libxl: do not set the PoD target on ARM

ARM does not implemented PoD and so returns ENOSYS from XENMEM_set_pod_target.

The correct solution here would be to check for ENOSYS in libxl, unfortunately
xc_domain_set_pod_target suffers from the same broken error reporting as the
rest of libxc and throws away the errno.

So for now conditionally define xc_domain_set_pod_target to return success
(which is what PoD does if nothing needs doing). xc_domain_get_pod_target sets
errno==-1 and returns -1, which matches the broken error reporting of the
existing function. It appears to have no in tree callers in any case.

The conditional should be removed once libxc has been fixed.

This makes ballooning (xl mem-set) work for ARM domains.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Julien Grall <julien.grall@linaro.org>
Cc: george.dunlap@citrix.com
x86: fix FS/GS base handling when using the fsgsbase feature

In that case, due to the respective instructions not being privileged,
we can't rely on our in-memory data to always be correct: While the
guest is running, it may change without us knowing about it. Therefore
we need to
- read the correct values from hardware during context switch out
  (save_segments())
- read the correct values from hardware during RDMSR emulation
- update in-memory values during guest mode change
  (toggle_guest_mode())

For completeness/consistency, WRMSR emulation is also being switched
to use wr[fg]sbase().

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: George Dunlap <george.dunlap@eu.citrix.com>
domctl: also pause domain for "extended" context updates

This is not just for consistency with "base" context updates, but
actually needed so that guest side accesses can't race with control
domain side updates.

This would have been a security issue if XSA-77 hadn't waived them on
the affected domctl operation.

While looking at the code I also spotted a redundant NULL check in the
"base" context update handling code, which is being removed.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: George Dunlap <george.dunlap@eu.citrix.com>
domctl: pause vCPU for context reads

"Base" context reads already paused the subject vCPU when being the
current one, but that special case isn't being properly dealt with
anyway (at the very least when x86's fsgsbase feature is in use), so
just disallow it.

"Extended" context reads so far didn't do any pausing.

While we can't avoid the reported data being stale by the time it
arrives at the caller, this way we at least guarantee that it is
consistent.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: George Dunlap <george.dunlap@eu.citrix.com>