Xen doesn't support CET-IBT yet. At a minimum, logic is required to enable it
for supervisor use, but the livepatch functionality needs to learn not to
overwrite ENDBR64 instructions.
Furthermore, Ubuntu enables -fcf-protection by default, along with a buggy
version of GCC-9 which objects to it in combination with
-mindirect-branch=thunk-extern (Fixed in GCC 10, 9.4).
Various objects (Xen boot path, Rombios 32 stubs) require .text to be at the
beginning of the object. These paths explode when .note.gnu.properties gets
put ahead of .text and we end up executing the notes data.
Disable -fcf-protection for all embedded objects.
Reported-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Users of EMBEDDED_EXTRA_CFLAGS already use -fno-asynchronous-unwind-tables, or
ought to. This shrinks the size of the rombios 32bit stubs in guest memory.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Linkers may put orphaned sections ahead of .text, which breaks the calling
requirements. A concrete example is Ubuntu's GCC-9 default of enabling
-fcf-protection which causes us to try and execute .note.gnu.properties during
Xen's boot.
Put .got.plt in its own section as it specifically needs preserving from the
linkers point of view, and discard everything else. This will hopefully be
more robust to other unexpected toolchain properties.
Fixes boot from an Ubuntu build of Xen.
Reported-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Tested-by: Jason Andryuk <jandryuk@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
GAS of at least version 2.34 complains:
hypercall_page.S: Assembler messages:
hypercall_page.S:24: Warning: symbol 'HYPERCALL_set_trap_table' already has its type set
...
hypercall_page.S:71: Warning: symbol 'HYPERCALL_arch_7' already has its type set
which is because the whole page is declared as STT_OBJECT already. Rearrange
.set with respect to .type in DECLARE_HYPERCALL() so STT_FUNC is already in
place.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
As per SDM rev 071 Cannon Lake has
- no CC3 residency MSR at 3FC,
- a CC1 residency MSR ar 660 (like various Atoms),
- a useless (always zero) CC3 residency MSR at 662.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 9ff09aefc4
master date: 2020-04-03 17:15:58 +0200
xc_cpuid_set() returns allocated memory via cpuid_res, which libxl needs to
free() seeing as it discards the results.
This is logically a backport of c/s b91825f628 "tools/libxc: Drop
config_transformed parameter from xc_cpuid_set()" but rewritten as one caller
of xc_cpuid_set() does use returned values.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
(cherry picked from commit c54de7d9df)
RDRAND/RDSEED can be hidden using cpuid= to mitigate SRBDS if microcode
isn't available.
This is part of XSA-320 / CVE-2020-0543.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Julien Grall <jgrall@amazon.com>
(cherry picked from commit 7028534d84)
See patch documentation and comments.
This is part of XSA-320 / CVE-2020-0543
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 6a49b9a792)
Updating microcode is less error prone when caches have been flushed and
depending on what exactly the microcode is updating. For example, some of the
issues around certain Broadwell parts can be addressed by doing a full cache
flush.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[Linux commit 91df9fdf51492aec9fed6b4cbd33160886740f47, ported to Xen]
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
master commit: 77c8294999
master date: 2020-05-05 20:18:19 +0100
stack++ can go into the next page and unmap_domain_page() will unmap the
wrong one, causing mapcache and memory corruption. Fix.
Signed-off-by: Hongyan Xia <hongyxia@amazon.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 2e3d87cc73
master date: 2020-05-05 16:13:44 +0100
PVHv1 dom0 was given access to all PHYSDEVOP hypercalls, and such
restriction was not removed when PVHv1 code was removed. As a result
the switch in hvm_physdev_op was more complicated than required, and
relied on PVHv2 dom0 not having PIRQ support in order to prevent
access to some PV specific PHYSDEVOPs.
Fix this by moving the default case to the bottom of the switch, since
there's no need for any fall through now. Also remove the hardware
domain check, as all the not explicitly listed PHYSDEVOPs are
forbidden for HVM domains.
Finally tighten the condition to allow usage of
PHYSDEVOP_pci_mmcfg_reserved: apart from having vPCI enabled it should
only be used by the hardware domain. Note that the code in
do_physdev_op is already restricting the call to privileged domains
only, but it can be further restricted to the hardware domain only, as
other privileged domains don't have access to MMCFG regions anyway.
Overall no functional change should arise from this change.
Reported-by: Julien Grall <jgrall@amazon.com>
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: a00e3737e0
master date: 2020-05-05 09:52:28 +0200
Several insns were missed when this function was first added. As far as
insns already supported by the emulator go - SMSW and {,V}STMXCSR were
wrongly considered r/o insns so far.
Insns like the VMX, SVM, or CET-SS ones, PTWRITE, or AMD's new SNP ones
are intentionally not covered just yet. VMPTRST is put there just to
complete the respective group.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: fc6fa977be
master date: 2020-05-05 09:50:54 +0200
XEN_DOMCTL_destroydomain creates a continuation if domain_kill -ERESTARTs.
In that scenario, it is possible to receive multiple _pirq_guest_unbind
calls for the same pirq from domain_kill, if the pirq has not yet been
removed from the domain's pirq_tree, as:
domain_kill()
-> domain_relinquish_resources()
-> pci_release_devices()
-> pci_clean_dpci_irq()
-> pirq_guest_unbind()
-> __pirq_guest_unbind()
Avoid recurring invocations of pirq_guest_unbind() by removing the pIRQ
from the tree being iterated after the first call there. In case such a
removed entry still has a softirq outstanding, record it and re-check
upon re-invocation.
Note that pirq_cleanup_check() gets relaxed beyond what's strictly
needed here, to avoid introducing an asymmetry there between HVM and PV
guests.
Reported-by: Varad Gautam <vrd@amazon.de>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Varad Gautam <vrd@amazon.de>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: 5b58dad089
master date: 2020-04-30 10:40:59 +0200
The GNTTABOP_cache_flush hypercall has a wrong test for hypercall
continuation, the test today is:
if ( rc > 0 || opaque_out != 0 )
Unfortunately this will be true even in case of an error (rc < 0),
possibly leading to very long lasting hypercalls (times of more
than an hour have been observed in a test case).
Correct the test condition to result in false with rc < 0 and set
opaque_out only if no error occurred, to be on the safe side.
Partially-suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
master commit: 46d8f69d46
master date: 2020-04-29 14:12:50 +0100
It turns out that a bug (since forever) in Xen causes XSAVE records to have
non-architectural behaviour on xsave-capable hardware, when a PV guest has not
touched the state.
In such a case, the data record returned from Xen is 2*uint64_t, both claiming
the (illegitimate) state of %xcr0 and %xcr0_accum being 0.
Adjust the bound in handle_x86_pv_vcpu_blob() to cope with this.
Fixes: 2a62c22715 "libxc/restore: Fix data auditing in handle_x86_pv_vcpu_blob()"
Reported-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wl@xen.org>
(cherry picked from commit 0729830cc4)
(cherry picked from commit d2aecd86c4)
The current logic only works by chance, in that XSAVE records also tend to be
a multiple of 128. Implement the missing logic for XSAVE.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit 2a62c22715)
(cherry picked from commit 0e2bbcf8b4)
handle_x86_pv_info() has a subtle bug. It uses an 'else if' chain with a
clause in the middle which doesn't exit unconditionally. In practice, this
means that when restoring a 32bit PV guest, later sanity checks are skipped.
Rework the logic a little to be simpler. There are exactly two valid
combinations of fields in X86_PV_INFO, so factor this out and check them all
in one go, before making adjustments to the current domain.
Once adjustments have been completed successfully, sanity check the result
against the X86_PV_INFO settings in one go, rather than piece-wise.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Ian Jackson <ian.jackson@eu.citrix.com>
(cherry picked from commit aafae0e800)
(cherry picked from commit 5932ee1e06)
The Expected and Got values are rendered in the wrong order.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Wei Liu <wl@xen.org>
(cherry picked from commit f50a4f6e24)
(cherry picked from commit 7b2225078b)
Commit 562a1c0f7e ("tools/xenstore: dont unlink connection object
twice") introduced a potential use after free problem in
domain_cleanup(): after calling talloc_unlink() for domain->conn
domain->conn is set to NULL. The problem is that domain is registered
as talloc child of domain->conn, so it might be freed by the
talloc_unlink() call.
With Xenstore being single threaded there are normally no concurrent
memory allocations running and freeing a virtual memory area normally
doesn't result in that area no longer being accessible. A problem
could occur only in case either a signal received results in some
memory allocation done in the signal handler (SIGHUP is a primary
candidate leading to reopening the log file), or in case the talloc
framework would do some internal memory allocation during freeing of
the memory (which would lead to clobbering of the freed domain
structure).
Fixes: 562a1c0f7e ("tools/xenstore: dont unlink connection object twice")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
(cherry picked from commit bb2a34fd74)
(cherry picked from commit dc5176d0f9)
The field 'sdss' was named 'dmss' before, commit 3148bebbf0 did the
renamed but didn't update the comment.
Fixes: 3148bebbf0 ("libxl: rename a field in libxl__domain_create_state")
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
(cherry picked from commit 035c4d7716)
(cherry picked from commit 5351a0a170fc7f6290d7d3d8be302d53d2426a87)
At the moment, the diagram is only indented with 2 spaces. So pandoc
will try to badly interpret it and not display it correctly.
Fix it by indenting all the block by 4 spaces (i.e an extra 2 spaces).
Fixes: d661611d08 ("docs/markdown: Switch to using pandoc, and fix underscore escaping")
Signed-off-by: Julien Grall <julien@xen.org>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
(cherry picked from commit 9c8705f8fe)
(cherry picked from commit 8b60270731)
The CONTROL command (former DEBUG command) isn't specified in the
xenstore protocol doc. Add it.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Backport: 4.9+
(cherry picked from commit f910c3ebc6)
DIRECTORY_PART was missing in docs/misc/xenstore.txt. Add it.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Paul Durrant <pdurrant@amazon.com>
Acked-by: Wei Liu <wl@xen.org>
Backport: 4.9+
(cherry picked from commit 94a0252c10)
Both script mkflask.sh and mkaccess_vector.sh generates multiple
files. Exploits the 'multi-target pattern rule' trick to call each
scripts only once.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 52f3f31985
master date: 2020-04-23 09:59:05 +0200
While I can't spot anything that would go wrong, just like the
respective hypercall only permits applicable bits to be set, we should
also do so when loading guest context.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: a62c6fe05c
master date: 2020-04-22 13:01:10 +0200
In preparation for the addition of VMASST_TYPE_runstate_update_flag
commit 72c538cca9 ("arm: add support for vm_assist hypercall") enabled
the hypercall for Arm. I consider it not logical that it then isn't also
exposed to x86 HVM guests (with the same single feature permitted to be
enabled as Arm has); Linux actually tries to use it afaict.
Rather than introducing yet another thin wrapper around vm_assist(),
make that function the main handler, requiring a per-arch
arch_vm_assist_valid_mask() definition instead.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
master commit: f13404d57f
master date: 2020-04-22 12:58:25 +0200
The CET spec has been published and guest kernels are starting to get support.
Introduce the CPUID and MSRs, and fully block the MSRs from guest use.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wl@xen.org>
master commit: 4803a67114
master date: 2020-04-21 16:52:03 +0100
The EPT page tables can be shared with the IOMMU as long as the page
sizes supported by EPT are also supported by the IOMMU.
Current code checks that both the IOMMU and EPT support the same page
sizes, but this is not strictly required, the IOMMU supporting more
page sizes than EPT is fine and shouldn't block page table sharing.
This is likely not a common case (IOMMU supporting more page sizes
than EPT), but should still be fixed for correctness.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
master commit: 3957e12c02
master date: 2020-04-21 10:54:56 +0200
It was observed that PCI MMIO and/or IO BARs were programmed with
memory and I/O decodes (bits 0 and 1 of PCI COMMAND register) enabled,
during PCI setup phase. This resulted in incorrect memory mapping as
soon as the lower half of the 64 bit bar is programmed.
This displaced any RAM mappings under 4G. After the
upper half is programmed PCI memory mapping is restored to its
intended high mem location, but the RAM displaced is not restored.
The OS then continues to boot and function until it tries to access
the displaced RAM at which point it suffers a page fault and crashes.
This patch address the issue by deferring enablement of memory and
I/O decode in command register until all the resources, like interrupts
I/O and/or MMIO BARs for all the PCI device functions are programmed,
in the descending order of memory requested.
Signed-off-by: Harsha Shamsundara Havanur <havanur@amazon.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: a8e0c228c7
master date: 2020-04-16 10:58:46 +0200
The PERFC_INCR() macro uses current->processor, but current is not valid
during early boot. This causes the following crash to occur if
e.g. rdmsr_safe() has to recover from a #GP fault.
(XEN) Early fatal page fault at e008:ffff82d0803b1a39 (cr2=0000000000000004, ec=0000)
(XEN) ----[ Xen-4.14-unstable x86_64 debug=y Not tainted ]----
(XEN) CPU: 0
(XEN) RIP: e008:[<ffff82d0803b1a39>] x86_64/entry.S#handle_exception_saved+0x64/0xb8
...
(XEN) Xen call trace:
(XEN) [<ffff82d0803b1a39>] R x86_64/entry.S#handle_exception_saved+0x64/0xb8
(XEN) [<ffff82d0806394fe>] F __start_xen+0x2cd/0x2980
(XEN) [<ffff82d0802000ec>] F __high_start+0x4c/0x4e
Furthermore, the PERFC_INCR() macro is wildly inefficient. There has been a
single caller for many releases now, so inline it and delete the macro
completely.
There is no need to reference current at all. What is actually needed is the
per_cpu_offset which can be obtained directly from the top-of-stack block.
This simplifies the counter handling to 3 instructions and no spilling to the
stack at all.
The same breakage from above is now handled properly:
(XEN) traps.c:1591: GPF (0000): ffff82d0806394fe [__start_xen+0x2cd/0x2980] -> ffff82d0803b3bfb
Reported-by: Julien Grall <jgrall@amazon.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Julien Grall <jgrall@amazon.com>
master commit: 615bfe42c6
master date: 2020-04-16 09:48:38 +0100
The XSA-226 fix was flawed - the backwards transformation on rc was done
too early, causing a continuation to not get invoked when the need for
preemption was determined at the very first iteration of the request.
This in particular means that all of the status fields of the individual
operations would be left untouched, i.e. set to whatever the caller may
or may not have initialized them to.
This is part of XSA-318.
Reported-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Tested-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
master commit: d6f22d5d9e
master date: 2020-04-14 14:42:32 +0200
Part of XSA-295 (c/s 863e74eb2c) inadvertently re-positioned the brackets,
changing the logic. If the _set_status() call fails, the grant_map hypercall
would fail with a status of 1 (rc != GNTST_okay) instead of the expected
negative GNTST_* error.
This error path can be taken due to bad guest state, and causes net/blk-back
in Linux to crash.
This is XSA-316.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
master commit: da0c66c8f4
master date: 2020-04-14 14:41:02 +0200
The rwlock unlock paths are using atomic_sub() to release the lock.
However the implementation of atomic_sub() rightfully doesn't contain a
memory barrier. On Arm, this means a processor is allowed to re-order
the memory access with the preceeding access.
In other words, the unlock may be seen by another processor before all
the memory accesses within the "critical" section.
The rwlock paths already contains barrier indirectly, but they are not
very useful without the counterpart in the unlock paths.
The memory barriers are not necessary on x86 because loads/stores are
not re-ordered with lock instructions.
So add arch_lock_release_barrier() in the unlock paths that will only
add memory barrier on Arm.
Take the opportunity to document each lock paths explaining why a
barrier is not necessary.
This is XSA-314.
Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Acked-by: Jan Beulich <jbeulich@suse.com>
master commit: 6890a04072
master date: 2020-04-14 14:37:11 +0200
Since a shared buffer can be written to by the guest, we may only read
the head and tail pointers from there (all other fields should only ever
be written to). Furthermore, for any particular operation the two values
must be read exactly once, with both checks and consumption happening
with the thus read values. (The backtrace related xenoprof_buf_space()
use in xenoprof_log_event() is an exception: The values used there get
re-checked by every subsequent xenoprof_add_sample().)
Since that code needed touching, also fix the double increment of the
lost samples count in case the backtrace related xenoprof_add_sample()
invocation in xenoprof_log_event() fails.
Where code is being touched anyway, add const as appropriate, but take
the opportunity to entirely drop the now unused domain parameter of
xenoprof_buf_space().
This is part of XSA-313.
Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
Reviewed-by: Wei Liu <wl@xen.org>
master commit: 50ef9a3cb2
master date: 2020-04-14 14:33:19 +0200
alloc_xenheap_pages() making use of MEMF_no_scrub is fine for Xen
internally used allocations, but buffers allocated to be shared with
(unpriviliged) guests need to be zapped of their prior content.
This is part of XSA-313.
Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wl@xen.org>
master commit: 0763a7ebfc
master date: 2020-04-14 14:32:33 +0200
Xen will only store the CompareValue as it can be derived from the
TimerValue (ARM DDI 0487E.a section D11.2.4):
CompareValue = (Counter[63:0] + SignExtend(TimerValue))[63:0]
While the TimerValue is a 32-bit signed value, our implementation
assumed it is a 32-bit unsigned value.
Signed-off-by: Jeff Kubascik <jeff.kubascik@dornerworks.com>
Acked-by: Julien Grall <julien@xen.org>
(cherry picked from commit 3c601c5f05)
The physical timer traps apply an offset so that time starts at 0 for
the guest. However, this offset is not currently applied to the physical
counter. Per the ARMv8 Reference Manual (ARM DDI 0487E.a), section
D11.2.4 Timers, the "Offset" between the counter and timer should be
zero for a physical timer. This removes the offset to make the timer and
counter consistent.
This also cleans up the physical timer implementation to better match
the virtual timer - both cval's now hold the hardware value.
In the case the guest sets cval to a time before Xen started, the correct
behavior is to expire the timer immediately. To do this, we set the expires
argument of set_timer to zero.
Signed-off-by: Jeff Kubascik <jeff.kubascik@dornerworks.com>
Acked-by: Julien Grall <julien@xen.org>
(cherry picked from commit f14f55b7ee)
When booting via EFI, the EFI memory map has information about memory
regions and their type. Improve the check for the type and attribute of
each memory region to figure out whether it is usable memory or not.
This patch brings the check on par with Linux v5.5-rc6 and makes more
memory reusable as normal memory by Xen (except that Linux also reuses
EFI_PERSISTENT_MEMORY, which we do not).
Specifically, this patch also reuses memory marked as
EfiLoaderCode/Data, and it uses both Attribute and Type for the check
(Attribute needs to be EFI_MEMORY_WB).
Reported-by: Roman Shaposhnik <roman@zededa.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Acked-by: Julien Grall <julien@xen.org>
(cherry picked from commit b31666c891)
The tx/rx fifo flags were not set when the vpl011 is initialized. This
is a problem for certain guests that are operating in polled mode, as a
guest will generally check the rx fifo empty flag to determine if there
is data before doing a read. The result is a continuous spam of the
message "vpl011: Unexpected IN ring buffer empty" before the first valid
character is received. This initializes the flag status register to the
default specified in the PL011 technical reference manual.
Signed-off-by: Jeff Kubascik <jeff.kubascik@dornerworks.com>
Acked-by: Julien Grall <julien@xen.org>
(cherry picked from commit b4637ed6cd)
Per the ARM Generic Interrupt Controller Architecture Specification (ARM
IHI 0069E), reserved registers should generally be treated as RAZ/WI.
To simplify the VGICv3 design and improve guest compatibility, treat the
default case for GICD and GICR registers as read_as_zero/write_ignore.
Signed-off-by: Jeff Kubascik <jeff.kubascik@dornerworks.com>
Acked-by: Julien Grall <julien@xen.org>
(cherry picked from commit 69da7d5440)
There is a bug in commit 5e4b419966 ("xen: credit2: only reset
credit on reset condition"). In fact, the aim of that commit was to
make sure that we do not perform too many credit reset operations
(which are not super cheap, and in an hot-path). But the check used
to determine whether a reset is necessary was the wrong one.
In fact, knowing just that some vCPUs have been skipped, while
traversing the runqueue (in runq_candidate()), is not enough. We
need to check explicitly whether the first vCPU in the runqueue
has a negative amount of credit.
Since a trace record is changed, this patch updates xentrace format file
and xenalyze as well
This should be backported.
Signed-off-by: Dario Faggioli <dfaggioli@suse.com>
Acked-by: George Dunlap <george.dunlap@citrix.com>
master commit: dae7b62e97
master date: 2020-04-03 10:46:53 +0200
There have been report of stalls of guest vCPUs, when Credit2 was used.
It seemed like these vCPUs were not getting scheduled for very long
time, even under light load conditions (e.g., during dom0 boot).
Investigations led to the discovery that --although rarely-- it can
happen that a vCPU manages to run for very long timeslices. In Credit2,
this means that, when runtime accounting happens, the vCPU will lose a
large quantity of credits. This in turn may lead to the vCPU having less
credits than the idle vCPUs (-2^30). At this point, the scheduler will
pick the idle vCPU, instead of the ready to run vCPU, for a few
"epochs", which often times is enough for the guest kernel to think the
vCPU is not responding and crashing.
An example of this situation is shown here. In fact, we can see d0v1
sitting in the runqueue while all the CPUs are idle, as it has
-1254238270 credits, which is smaller than -2^30 = −1073741824:
(XEN) Runqueue 0:
(XEN) ncpus = 28
(XEN) cpus = 0-27
(XEN) max_weight = 256
(XEN) pick_bias = 22
(XEN) instload = 1
(XEN) aveload = 293391 (~111%)
(XEN) idlers: 00,00000000,00000000,00000000,00000000,00000000,0fffffff
(XEN) tickled: 00,00000000,00000000,00000000,00000000,00000000,00000000
(XEN) fully idle cores: 00,00000000,00000000,00000000,00000000,00000000,0fffffff
[...]
(XEN) Runqueue 0:
(XEN) CPU[00] runq=0, sibling=00,..., core=00,...
(XEN) CPU[01] runq=0, sibling=00,..., core=00,...
[...]
(XEN) CPU[26] runq=0, sibling=00,..., core=00,...
(XEN) CPU[27] runq=0, sibling=00,..., core=00,...
(XEN) RUNQ:
(XEN) 0: [0.1] flags=0 cpu=5 credit=-1254238270 [w=256] load=262144 (~100%)
We certainly don't want, under any circumstance, this to happen.
Let's, therefore, define a minimum amount of credits a vCPU can have.
During accounting, we make sure that, for however long the vCPU has
run, it will never get to have less than such minimum amount of
credits. Then, we set the credits of the idle vCPU to an even
smaller value.
NOTE: investigations have been done about _how_ it is possible for a
vCPU to execute for so much time that its credits becomes so low. While
still not completely clear, there are evidence that:
- it only happens very rarely,
- it appears to be both machine and workload specific,
- it does not look to be a Credit2 (e.g., as it happens when
running with Credit1 as well) issue, or a scheduler issue.
This patch makes Credit2 more robust to events like this, whatever
the cause is, and should hence be backported (as far as possible).
Reported-by: Glen <glenbarney@gmail.com>
Reported-by: Tomas Mozes <hydrapolic@gmail.com>
Signed-off-by: Dario Faggioli <dfaggioli@suse.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
master commit: 36f3662f27
master date: 2020-04-03 10:45:43 +0200
cpu_request_microcode() doesn't know the buffer is at least 4 bytes long
before inspecting UCODE_MAGIC.
install_equiv_cpu_table() doesn't know the boundary of the buffer it is
interpreting as an equivalency table. This case was clearly observed at one
point in the past, given the subsequent overrun detection, but without
comprehending that the damage was already done.
Make the logic consistent with container_fast_forward() and pass size_left in
to install_equiv_cpu_table().
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 718d143200
master date: 2020-04-01 14:00:12 +0100
The involved comparison was, very likely inadvertently, converted from
>= to > when making changes unrelated to the actual family range.
Fixes: 9841eb71ea ("x86/cpuid: Drop a guests cached x86 family and model information")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Paul Durrant <paul@xen.org>
master commit: 5d515b1c29
master date: 2020-04-01 12:28:30 +0200
find_equiv_cpu_id() loops until it finds a 0 installed_cpu entry. Well formed
AMD microcode containers have this property.
Extend the checking in install_equiv_cpu_table() to reject tables which don't
have a sentinal at the end.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 1f97b6b9f1
master date: 2020-03-27 13:13:26 +0000
x86_cpuid_policy_fill_native() should, as it did originally, iterate
over all subleaves here as well as over all main leaves. Switch to
using a "<= MIN()"-based approach similar to that used in
x86_cpuid_copy_to_buffer(). Also follow this for the extended main
leaves then.
Fixes: 1bd2b75053 ("libx86: Fix 32bit stubdom build of x86_cpuid_policy_fill_native()")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: eb0bad81fc
master date: 2020-03-27 11:40:59 +0100
Andrew Cooper
Jan Beulich
Ashok Raj
Hongyan Xia
Roger Pau Monné
Juergen Gross
Anthony PERARD
Julien Grall
Harsha Shamsundara Havanur
Ross Lagerwall
Julien Grall
Jeff Kubascik
Stefano Stabellini
Dario Faggioli