At the moment the P2M page tables will be freed when the domain structure
is freed without any preemption. As the P2M is quite large, iterating
through this may take more time than it is reasonable without intermediate
preemption (to run softirqs and perhaps scheduler).
Split p2m_teardown() in two parts: one preemptible and called when
relinquishing the resources, the other one non-preemptible and called
when freeing the domain structure.
As we are now freeing the P2M pages early, we also need to prevent
further allocation if someone call p2m_set_entry() past p2m_teardown()
(I wasn't able to prove this will never happen). This is done by
the checking domain->is_dying from previous patch in p2m_set_entry().
Similarly, we want to make sure that no-one can accessed the free
pages. Therefore the root is cleared before freeing pages.
This is part of CVE-2022-33746 / XSA-410.
Signed-off-by: Julien Grall <jgrall@amazon.com>
Signed-off-by: Henry Wang <Henry.Wang@arm.com>
Tested-by: Henry Wang <Henry.Wang@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
master commit: 3202084566
master date: 2022-10-11 14:20:56 +0200
During the domain destroy process, the domain will still be accessible
until it is fully destroyed. So does the P2M because we don't bail
out early if is_dying is non-zero. If a domain has permission to
modify the other domain's P2M (i.e. dom0, or a stubdomain), then
foreign mapping can be added past relinquish_p2m_mapping().
Therefore, we need to prevent mapping to be added when the domain
is dying. This commit prevents such adding of mapping by adding the
d->is_dying check to p2m_set_entry(). Also this commit enhances the
check in relinquish_p2m_mapping() to make sure that no mappings can
be added in the P2M after the P2M lock is released.
This is part of CVE-2022-33746 / XSA-410.
Signed-off-by: Julien Grall <jgrall@amazon.com>
Signed-off-by: Henry Wang <Henry.Wang@arm.com>
Tested-by: Henry Wang <Henry.Wang@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
master commit: 3ebe773293
master date: 2022-10-11 14:20:18 +0200
The last "wildcard" use of either function went away with f591755823
("IOMMU/PCI: don't let domain cleanup continue when device de-assignment
failed"). Don't allow them to be called this way anymore. Besides
simplifying the code this also fixes two bugs:
1) When seg != -1, the outer loops should have been terminated after the
first iteration, or else a device with the same BDF but on another
segment could be found / returned.
Reported-by: Rahul Singh <rahul.singh@arm.com>
2) When seg == -1 calling get_pseg() is bogus. The function (taking a
u16) would look for segment 0xffff, which might exist. If it exists,
we might then find / return a wrong device.
In pci_get_pdev_by_domain() also switch from using the per-segment list
to using the per-domain one, with the exception of the hardware domain
(see the code comment there).
While there also constify "pseg" and drop "pdev"'s already previously
unnecessary initializer.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Rahul Singh <rahul.singh@arm.com>
Tested-by: Rahul Singh <rahul.singh@arm.com>
master commit: 8cf6e07389
master date: 2022-08-12 08:34:33 +0200
Commit 68f5aac012 ("build: suppress future GNU ld warning about RWX
load segments") didn't quite cover all the cases: Apparently I missed
ones in the building of 32-bit helper objects because of only looking at
incremental builds (where those wouldn't normally be re-built). Clone
the workaround there to the specific Makefile in question.
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: 3eb1865ae3
master date: 2022-08-11 17:45:12 +0200
This should only be called for the boot CPU to avoid calling _init code
after it has been unloaded.
Fixes: 062868a5a8 ("x86/amd: Work around CLFLUSH ordering on older parts")
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 31b41ce858
master date: 2022-08-11 17:44:26 +0200
The PBRSB_NO bit indicates that the CPU is not vulnerable to the Post-Barrier
RSB speculative vulnerability.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: b874e47eb1
master date: 2022-08-11 16:19:50 +0100
"-sdl" is deprecated upstream since 6695e4c0fd9e ("softmmu/vl:
Deprecate the -sdl and -curses option"), QEMU v6.2, and the option is
removed by 707d93d4abc6 ("ui: Remove deprecated options "-sdl" and
"-curses""), in upcoming QEMU v7.1.
Instead, use "-display sdl", available since 1472a95bab1e ("Introduce
-display argument"), before QEMU v1.0.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
master commit: 41fcb3af8a
master date: 2022-08-11 11:47:11 +0200
Right now, affinity for dom0 vCPUs is setup in two steps. This is a
problem as, at least in Credit2, unit_insert() sees and uses the
"intermediate" affinity, and place the vCPUs on CPUs where they cannot
be run. And this in turn results in boot hangs, if the "dom0_nodes"
parameter is used.
Fix this by setting up the affinity properly once and for all, in
sched_init_vcpu() called by create_vcpu().
Note that, unless a soft-affinity is explicitly specified for dom0 (by
using the relaxed mode of "dom0_nodes") we set it to the default, which
is all CPUs, instead of computing it basing on hard affinity (if any).
This is because hard and soft affinity should be considered as
independent user controlled properties. In fact, if we dor derive dom0's
soft-affinity from its boot-time hard-affinity, such computed value will
continue to be used even if later the user changes the hard-affinity.
And this could result in the vCPUs behaving differently than what the
user wanted and expects.
Fixes: dafd936ddd ("Make credit2 the default scheduler")
Reported-by: Olaf Hering <ohering@suse.de>
Signed-off-by: Dario Faggioli <dfaggioli@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: c79e4d209b
master date: 2022-08-11 11:46:22 +0200
commit e46474278a ("x86/intel: Expose MSR_ARCH_CAPS to dom0") started
exposing MSR_ARCH_CAPS to dom0. More bits in MSR_ARCH_CAPS have since
been defined, but they haven't been exposed. Update the list to allow
them through.
As one example, this allows a Linux Dom0 to know that it has the
appropriate microcode via FB_CLEAR. Notably, and with the updated
microcode, this changes dom0's
/sys/devices/system/cpu/vulnerabilities/mmio_stale_data changes from:
"Vulnerable: Clear CPU buffers attempted, no microcode; SMT Host state unknown"
to:
"Mitigation: Clear CPU buffers; SMT Host state unknown"
This exposes the MMIO Stale Data and Intel Branch History Injection
(BHI) controls as well as the page size change MCE issue bit.
Fixes: commit 2ebe8fe9b7 ("x86/spec-ctrl: Enumeration for MMIO Stale Data controls")
Fixes: commit cea9ae0622 ("x86/spec-ctrl: Enumeration for new Intel BHI controls")
Fixes: commit 59e89cdabc ("x86/vtx: Disable executable EPT superpages to work around CVE-2018-12207")
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: e83cd54611
master date: 2022-08-09 16:35:25 +0100
There is a corner case where a VT-x guest which manages to reliably trigger
non-fatal #MC's could evade the rogue RSB speculation protections that were
supposed to be in place.
This is a lack of defence in depth; Xen does not architecturally execute more
RET than CALL instructions, so an attacker would have to locate a different
gadget (e.g. SpectreRSB) first to execute a transient path of excess RET
instructions.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: e570e8d520
master date: 2022-08-05 12:16:24 +0100
The latest Intel manual now says the X2APIC reserved range is only
0x800 to 0x8ff (NOT 0xbff).
This changed between SDM 68 (Nov 2018) and SDM 69 (Jan 2019).
The AMD manual documents 0x800-0x8ff too.
There are non-X2APIC MSRs in the 0x900-0xbff range now:
e.g. 0x981 is IA32_TME_CAPABILITY, an architectural MSR.
The new MSR in this range appears to have been introduced in Icelake,
so this commit should be backported to Xen versions supporting Icelake.
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 13316827fa
master date: 2022-07-27 12:57:10 +0200
Introduce support in libxl for fetching the default backend trusted
option for disk and nic devices.
Users can set LIBXL_{DISK,NIC}_BACKEND_UNTRUSTED environment variable
to notify libxl of whether the backends for disk and nic devices
should be trusted. Such information is passed into the frontend so it
can take the appropriate measures.
This is part of XSA-403.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
In common/memory.c the ifdef code surrounding ptdom_max_order is
using HAS_PASSTHROUGH instead of CONFIG_HAS_PASSTHROUGH, fix the
problem using the correct macro.
Fixes: e0d44c1f94 ("build: convert HAS_PASSTHROUGH use to Kconfig")
Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 5707470bf3
master date: 2022-07-26 08:33:46 +0200
Passing -mno-sse alone is not enough: The compiler may still find
(questionable) reasons to use MMX insns. In particular with gcc12 use
of MOVD+PUNPCKLDQ+MOVQ was observed in an apparent attempt to auto-
vectorize the storing of two adjacent zeroes, 32 bits each.
Reported-by: ChrisD <chris@dalessio.org>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 6fe2e39a02
master date: 2022-07-20 15:48:49 +0200
Already ISE rev 044 added text to this effect; rev 045 further dropped
leftover earlier text indicating the contrary:
- ENQCMD requires the low 32 bits of the memory operand to be clear,
- ENDCMDS requires bits 20...30 of the memory operand to be clear.
Fixes: d273859687 ("x86emul: support ENQCMD insns")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: d620c66bdb
master date: 2022-07-20 15:46:48 +0200
While a number of issues we previously had with pre-release gcc12 were
fixed in the final release, we continue to have one issue (with multiple
instances) when doing release builds (i.e. at higher optimization
levels): The compiler takes issue with subtracting (always 1 in our
case) from artifical labels (expressed as array) marking the end of
certain regions. This isn't an unreasonable position to take. Simply
hide the "array-ness" by casting to an integer type. To keep things
looking consistently, apply the same cast also on the respective
expressions dealing with the starting addresses. (Note how
efi_arch_memory_setup()'s l2_table_offset() invocations avoid a similar
issue by already having the necessary casts.) In is_xen_fixed_mfn()
further switch from __pa() to virt_to_maddr() to better match the left
sides of the <= operators.
Reported-by: Charles Arnold <carnold@suse.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: 9723507daf
master date: 2022-07-19 08:37:29 +0200
There are command line controls for this and the default also isn't "always
enable when hardware supports it", which logging should take into account.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: fdbf8bdfeb
master date: 2022-07-19 08:36:53 +0200
Move the "credit expired" loop exit to the middle of the loop,
immediately after "return true". This way having reached the goal on the
last iteration would be reported as success to the caller, rather than
as "timed out".
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
master commit: d8f8cb8bdd
master date: 2022-07-18 17:48:18 +0200
In case of maxmem != memsize the E820 map of the PVH stubdom is wrong,
as it is missing the RAM above memsize.
Additionally the memory map should only specify the Xen special pages
as reserved.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
master commit: 134d53f577
master date: 2022-07-12 15:25:20 +0200
While in principle possible also under other conditions as long as other
parallel operations potentially consuming memory aren't "locked out", in
particular with IOMMU large page mappings used in Dom0 (for PV when in
strict mode; for PVH when not sharing page tables with HAP) ballooning
out of individual pages can actually lead to less free memory available
afterwards. This is because to split a large page, one or more page
table pages are necessary (one per level that is split).
When rebooting a guest I've observed freemem() to fail: A single page
was required to be ballooned out (presumably because of heap
fragmentation in the hypervisor). This ballooning out of a single page
of course went fast, but freemem() then found that it would require to
balloon out another page. This repeating just another time leads to the
function to signal failure to the caller - without having come anywhere
near the designated 30s that the whole process is allowed to not make
any progress at all.
Convert from a simple retry count to actually calculating elapsed time,
subtracting from an initial credit of 30s. Don't go as far as limiting
the "wait_secs" value passed to libxl_wait_for_memory_target(), though.
While this leads to the overall process now possibly taking longer (if
the previous iteration ended very close to the intended 30s), this
compensates to some degree for the value passed really meaning "allowed
to run for this long without making progress".
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
master commit: e58370df76
master date: 2022-07-12 15:25:00 +0200
When this logic was moved, it was moved across the point where nx is
updated to hold the new type for the page. IOW originally it was
equivalent to using x (and perhaps x would better have been used), but
now it isn't anymore. Switch to using x, which then brings things in
line again with the slightly earlier comment there (now) talking about
transitions _from_ writable.
I have to confess though that I cannot make a direct connection between
the reported observed behavior of guests leaving several pages around
with pending general references and the change here. Repeated testing,
nevertheless, confirms the reported issue is no longer there.
This is CVE-2022-33745 / XSA-408.
Reported-by: Charles Arnold <carnold@suse.com>
Fixes: 8cc5036bc3 ("x86/pv: Fix ABAC cmpxchg() race in _get_page_type()")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: a9949efb28
master date: 2022-07-26 14:54:34 +0200
Branch Type Confusion affects AMD/Hygon CPUs on Zen2 and earlier. To
mitigate, we require SMT safety (STIBP on Zen2, no-SMT on Zen1), and to issue
an IBPB on each entry to Xen, to flush the BTB.
Due to performance concerns, dom0 (which is trusted in most configurations) is
excluded from protections by default.
Therefore:
* Use STIBP by default on Zen2 too, which now means we want it on by default
on all hardware supporting STIBP.
* Break the current IBPB logic out into a new function, extending it with
IBPB-at-entry logic.
* Change the existing IBPB-at-ctxt-switch boolean to be tristate, and disable
it by default when IBPB-at-entry is providing sufficient safety.
If all PV guests on the system are trusted, then it is recommended to boot
with `spec-ctrl=ibpb-entry=no-pv`, as this will provide an additional marginal
perf improvement.
This is part of XSA-407 / CVE-2022-23825.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit d8cb7e0f06)
... as instructed in the Branch Type Confusion whitepaper.
This is part of XSA-407.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
(cherry picked from commit 9deaf2d932)
BTC_NO indicates that hardware is not succeptable to Branch Type Confusion.
Zen3 CPUs don't suffer BTC.
This is part of XSA-407.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 76cb04ad64)
We are going to need this to mitigate Branch Type Confusion on AMD/Hygon CPUs,
but as we've talked about using it in other cases too, arrange to support it
generally. However, this is also very expensive in some cases, so we're going
to want per-domain controls.
Introduce SCF_ist_ibpb and SCF_entry_ibpb controls, adding them to the IST and
DOM masks as appropriate. Also introduce X86_FEATURE_IBPB_ENTRY_{PV,HVM} to
to patch the code blocks.
For SVM, the STGI is serialising enough to protect against Spectre-v1 attacks,
so no "else lfence" is necessary. VT-x will use use the MSR host load list,
so doesn't need any code in the VMExit path.
For the IST path, we can't safely check CPL==0 to skip a flush, as we might
have hit an entry path before it's IBPB. As IST hitting Xen is rare, flush
irrespective of CPL. A later path, SCF_ist_sc_msr, provides Spectre-v1
safety.
For the PV paths, we know we're interrupting CPL>0, while for the INTR paths,
we can safely check CPL==0. Only flush when interrupting guest context.
An "else lfence" is needed for safety, but we want to be able to skip it on
unaffected CPUs, so the block wants to be an alternative, which means the
lfence has to be inline rather than UNLIKELY() (the replacement block doesn't
have displacements fixed up for anything other than the first instruction).
As with SPEC_CTRL_ENTRY_FROM_INTR_IST, %rdx is 0 on entry so rely on this to
shrink the logic marginally. Update the comments to specify this new
dependency.
This is part of XSA-407.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 53a570b285)
We are shortly going to add a conditional IBPB in this path.
Therefore, we cannot hold spec_ctrl_flags in %eax, and rely on only clobbering
it after we're done with its contents. %rbx is available for use, and the
more normal register to hold preserved information in.
With %rax freed up, use it instead of %rdx for the RSB tmp register, and for
the adjustment to spec_ctrl_flags.
This leaves no use of %rdx, except as 0 for the upper half of WRMSR. In
practice, %rdx is 0 from SAVE_ALL on all paths and isn't likely to change in
the foreseeable future, so update the macro entry requirements to state this
dependency. This marginal optimisation can be revisited if circumstances
change.
No practical change.
This is part of XSA-407.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit e9b8d31981)
We are about to introduce the use of IBPB at different points in Xen, making
opt_ibpb ambiguous. Rename it to opt_ibpb_ctxt_switch.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit a8e5ef079d)
We are about to introduce SCF_ist_ibpb, at which point SCF_ist_wrmsr becomes
ambiguous.
No functional change.
This is part of XSA-407.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 76d6a36f64)
We are shortly going to need to context switch new bits in both the vcpu and
S3 paths. Introduce SCF_IST_MASK and SCF_DOM_MASK, and rework d->arch.verw
into d->arch.spec_ctrl_flags to accommodate.
No functional change.
This is part of XSA-407.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 5796912f72)
libxl__xs_directory() can potentially return NULL without setting `n`.
As `n` isn't initialised, we need to check libxl__xs_directory()
return value before checking `n`. Otherwise, `n` might be non-zero
with `bdfs` NULL which would lead to a segv.
Fixes: 57bff091f4 ("libxl: add 'name' field to 'libxl_device_pci' in the IDL...")
Reported-by: "G.R." <firemeteor@users.sourceforge.net>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Tested-by: "G.R." <firemeteor@users.sourceforge.net>
master commit: d778089ac7
master date: 2022-07-12 08:38:51 +0200
Missing prototype of asprintf() without _GNU_SOURCE.
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Henry Wang <Henry.Wang@arm.com>
master commit: d693b22733
master date: 2022-07-12 08:38:35 +0200
Support controling the PV/HVM suboption of msr-sc/rsb/md-clear, which
previously wasn't possible.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 27357c394b
master date: 2022-07-11 15:21:35 +0100
This will help parsing a sub-option which has boolean and non-boolean options
available.
First, rework 'int val' into 'bool has_neg_prefix'. This inverts it's value,
but the resulting logic is far easier to follow.
Second, reject anything of the form 'no-$FOO=' which excludes ambiguous
constructs such as 'no-$foo=yes' which have never been valid.
This just leaves the case where everything is otherwise fine, but parse_bool()
can't interpret the provided string.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 382326cac5
master date: 2022-07-11 15:21:35 +0100
This was an oversight from when unpriv-mmio was introduced.
Fixes: 8c24b70fed ("x86/spec-ctrl: Add spec-ctrl=unpriv-mmio")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 4cdb519d79
master date: 2022-07-11 15:21:35 +0100
xc_psr.c:161:5: error: conflicting types for 'xc_psr_cmt_get_data'
due to enum/integer mismatch;
Signed-off-by: Charles Arnold <carnold@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
master commit: 8eeae8c2b4
master date: 2022-07-06 13:06:40 +0200
STIBP and PSFD are slightly weird bits, because they're both implied by other
bits in MSR_SPEC_CTRL. Add fine grain controls for them, and take the
implications into account when setting IBRS/SSBD.
Rearrange the IBPB text/variables/logic to keep all the MSR_SPEC_CTRL bits
together, for consistency.
However, AMD have a hardware hint CPUID bit recommending that STIBP be set
unilaterally. This is advertised on Zen3, so follow the recommendation.
Furthermore, in such cases, set STIBP behind the guest's back for now. This
has negligible overhead for the guest, but saves a WRMSR on vmentry. This is
the only default change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: fef244b179
master date: 2022-06-30 18:07:13 +0100
Back at the time of the original Spectre-v2 fixes, it was recommended to clear
MSR_SPEC_CTRL when going idle. This is because of the side effects on the
sibling thread caused by the microcode IBRS and STIBP implementations which
were retrofitted to existing CPUs.
However, there are no relevant cross-thread impacts for the hardware
IBRS/STIBP implementations, so this logic should not be used on Intel CPUs
supporting eIBRS, or any AMD CPUs; doing so only adds unnecessary latency to
the idle path.
Furthermore, there's no point playing with MSR_SPEC_CTRL in the idle paths if
SMT is disabled for other reasons.
Fixes: 8d03080d2a ("x86/spec-ctrl: Cease using thunk=lfence on AMD")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
master commit: ffc7694e0c
master date: 2022-06-30 18:07:13 +0100
At the moment, corrupt() is neither checking for allocation failure
nor freeing the allocated memory.
Harden the code by printing ENOMEM if the allocation failed and
free 'str' after the last use.
This is not considered to be a security issue because corrupt() should
only be called when Xenstored thinks the database is corrupted. Note
that the trigger (i.e. a guest reliably provoking the call) would be
a security issue.
Fixes: 06d17943f0 ("Added a basic integrity checker, and some basic ability to recover from store")
Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
master commit: db3382dd4f
master date: 2022-06-23 13:44:10 +0100
The ehci<n> number was parsed but ignored.
Fixes: 322ecbe4ac ("console: add EHCI debug port based serial console")
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: d6d0cb659f
master date: 2022-06-16 14:23:37 +0100
As per [1] the expansion of the pirq_dpci() macro causes a -Waddress
controlled warning (enabled implicitly in our builds, if not by default)
tying the middle part of the involved conditional expression to the
surrounding boolean context. Work around this by introducing a local
inline function in the affected source file.
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102967
master commit: 80ad8db8a4
master date: 2022-06-15 10:19:32 +0200
Exporting a variable with a dash doesn't work reliably, they may be
striped from the environment when calling a sub-make or sub-shell.
CFLAGS-stack-boundary start to be removed from env in patch "build:
set ALL_OBJS in main Makefile; move prelink.o to main Makefile" when
running `make "ALL_OBJS=.."` due to the addition of the quote. At
least in my empirical tests.
Fixes: 2740d96efd ("xen/build: have the root Makefile generates the CFLAGS")
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
master commit: aa390d513a
master date: 2022-01-28 11:44:33 +0100
Per Xen's support statement, PCI passthrough should be to trusted domains
because the overall system security depends on factors outside of Xen's
control.
As such, Xen, in a supported configuration, is not vulnerable to DRPW/SBDR.
However, users who have risk assessed their configuration may be happy with
the risk of DoS, but unhappy with the risk of cross-domain data leakage. Such
users should enable this option.
On CPUs vulnerable to MDS, the existing mitigations are the best we can do to
mitigate MMIO cross-domain data leakage.
On CPUs fixed to MDS but vulnerable MMIO stale data leakage, this option:
* On CPUs susceptible to FBSDP, mitigates cross-domain fill buffer leakage
using FB_CLEAR.
* On CPUs susceptible to SBDR, mitigates RNG data recovery by engaging the
srb-lock, previously used to mitigate SRBDS.
Both mitigations require microcode from IPU 2022.1, May 2022.
This is part of XSA-404.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 8c24b70fed)
The three *_NO bits indicate non-susceptibility to the SSDP, FBSDP and PSDP
data movement primitives.
FB_CLEAR indicates that the VERW instruction has re-gained it's Fill Buffer
flushing side effect. This is only enumerated on parts where VERW had
previously lost it's flushing side effect due to the MDS/TAA vulnerabilities
being fixed in hardware.
FB_CLEAR_CTRL is available on a subset of FB_CLEAR parts where the Fill Buffer
clearing side effect of VERW can be turned off for performance reasons.
This is part of XSA-404.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit 2ebe8fe9b7)
Currently, VERW flushing to mitigate MDS is boot time conditional per domain
type. However, to provide mitigations for DRPW (CVE-2022-21166), we need to
conditionally use VERW based on the trustworthiness of the guest, and the
devices passed through.
Remove the PV/HVM alternatives and instead issue a VERW on the return-to-guest
path depending on the SCF_verw bit in cpuinfo spec_ctrl_flags.
Introduce spec_ctrl_init_domain() and d->arch.verw to calculate the VERW
disposition at domain creation time, and context switch the SCF_verw bit.
For now, VERW flushing is used and controlled exactly as before, but later
patches will add per-domain cases too.
No change in behaviour.
This is part of XSA-404.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
(cherry picked from commit e06b95c1d4)
While PGT_pae_xen_l2 will be zapped once the type refcount of an L2 page
reaches zero, it'll be retained as long as the type refcount is non-
zero. Hence any checking against the requested type needs to either zap
the bit from the type or include it in the used mask.
Fixes: 9186e96b19 ("x86/pv: Clean up _get_page_type()")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: c2095ac76b
master date: 2022-06-10 10:21:06 +0200
There are legitimate uses of WC mappings of RAM, e.g. for DMA buffers with
devices that make non-coherent writes. The Linux sound subsystem makes
extensive use of this technique.
For such usecases, the guest's DMA buffer is mapped and consistently used as
WC, and Xen doesn't interact with the buffer.
However, a mischevious guest can use WC mappings to deliberately create
non-coherency between the cache and RAM, and use this to trick Xen into
validating a pagetable which isn't actually safe.
Allocate a new PGT_non_coherent to track the non-coherency of mappings. Set
it whenever a non-coherent writeable mapping is created. If the page is used
as anything other than PGT_writable_page, force a cache flush before
validation. Also force a cache flush before the page is returned to the heap.
This is CVE-2022-26364, part of XSA-402.
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: George Dunlap <george.dunlap@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: c1c9cae3a9
master date: 2022-06-09 14:23:37 +0200
On pre-CLFLUSHOPT AMD CPUs, CLFLUSH is weakely ordered with everything,
including reads and writes to the address, and LFENCE/SFENCE instructions.
This creates a multitude of problematic corner cases, laid out in the manual.
Arrange to use MFENCE on both sides of the CLFLUSH to force proper ordering.
This is part of XSA-402.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 062868a5a8
master date: 2022-06-09 14:23:07 +0200
Subsequent changes will want a fully flushing version.
Use the new helper rather than opencoding it in flush_area_local(). This
resolves an outstanding issue where the conditional sfence is on the wrong
side of the clflushopt loop. clflushopt is ordered with respect to older
stores, not to younger stores.
Rename gnttab_cache_flush()'s helper to avoid colliding in name.
grant_table.c can see the prototype from cache.h so the build fails
otherwise.
This is part of XSA-402.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 9a67ffee33
master date: 2022-06-09 14:22:38 +0200
Julien Grall