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commit 1dc6ff02c8bf77d71b9b5d11cbc9df77cfb28626 upstream
Similar to MDS and TAA, print a warning if SMT is enabled for the MMIO
Stale Data vulnerability.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a992b8a4682f119ae035a01b40d4d0665c4a2875 upstream
The Shared Buffers Data Sampling (SBDS) variant of Processor MMIO Stale
Data vulnerabilities may expose RDRAND, RDSEED and SGX EGETKEY data.
Mitigation for this is added by a microcode update.
As some of the implications of SBDS are similar to SRBDS, SRBDS mitigation
infrastructure can be leveraged by SBDS. Set X86_BUG_SRBDS and use SRBDS
mitigation.
Mitigation is enabled by default; use srbds=off to opt-out. Mitigation
status can be checked from below file:
/sys/devices/system/cpu/vulnerabilities/srbds
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 22cac9c677c95f3ac5c9244f8ca0afdc7c8afb19 upstream
Currently, Linux disables SRBDS mitigation on CPUs not affected by
MDS and have the TSX feature disabled. On such CPUs, secrets cannot
be extracted from CPU fill buffers using MDS or TAA. Without SRBDS
mitigation, Processor MMIO Stale Data vulnerabilities can be used to
extract RDRAND, RDSEED, and EGETKEY data.
Do not disable SRBDS mitigation by default when CPU is also affected by
Processor MMIO Stale Data vulnerabilities.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 8d50cdf8b8341770bc6367bce40c0c1bb0e1d5b3 upstream
Add the sysfs reporting file for Processor MMIO Stale Data
vulnerability. It exposes the vulnerability and mitigation state similar
to the existing files for the other hardware vulnerabilities.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 99a83db5a605137424e1efe29dc0573d6a5b6316 upstream
When the CPU is affected by Processor MMIO Stale Data vulnerabilities,
Fill Buffer Stale Data Propagator (FBSDP) can propagate stale data out
of Fill buffer to uncore buffer when CPU goes idle. Stale data can then
be exploited with other variants using MMIO operations.
Mitigate it by clearing the Fill buffer before entering idle state.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Co-developed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e5925fb867290ee924fcf2fe3ca887b792714366 upstream
MDS, TAA and Processor MMIO Stale Data mitigations rely on clearing CPU
buffers. Moreover, status of these mitigations affects each other.
During boot, it is important to maintain the order in which these
mitigations are selected. This is especially true for
md_clear_update_mitigation() that needs to be called after MDS, TAA and
Processor MMIO Stale Data mitigation selection is done.
Introduce md_clear_select_mitigation(), and select all these mitigations
from there. This reflects relationships between these mitigations and
ensures proper ordering.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 8cb861e9e3c9a55099ad3d08e1a3b653d29c33ca upstream
Processor MMIO Stale Data is a class of vulnerabilities that may
expose data after an MMIO operation. For details please refer to
Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst.
These vulnerabilities are broadly categorized as:
Device Register Partial Write (DRPW):
Some endpoint MMIO registers incorrectly handle writes that are
smaller than the register size. Instead of aborting the write or only
copying the correct subset of bytes (for example, 2 bytes for a 2-byte
write), more bytes than specified by the write transaction may be
written to the register. On some processors, this may expose stale
data from the fill buffers of the core that created the write
transaction.
Shared Buffers Data Sampling (SBDS):
After propagators may have moved data around the uncore and copied
stale data into client core fill buffers, processors affected by MFBDS
can leak data from the fill buffer.
Shared Buffers Data Read (SBDR):
It is similar to Shared Buffer Data Sampling (SBDS) except that the
data is directly read into the architectural software-visible state.
An attacker can use these vulnerabilities to extract data from CPU fill
buffers using MDS and TAA methods. Mitigate it by clearing the CPU fill
buffers using the VERW instruction before returning to a user or a
guest.
On CPUs not affected by MDS and TAA, user application cannot sample data
from CPU fill buffers using MDS or TAA. A guest with MMIO access can
still use DRPW or SBDR to extract data architecturally. Mitigate it with
VERW instruction to clear fill buffers before VMENTER for MMIO capable
guests.
Add a kernel parameter mmio_stale_data={off|full|full,nosmt} to control
the mitigation.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f52ea6c26953fed339aa4eae717ee5c2133c7ff2 upstream
Processor MMIO Stale Data mitigation uses similar mitigation as MDS and
TAA. In preparation for adding its mitigation, add a common function to
update all mitigations that depend on MD_CLEAR.
[ bp: Add a newline in md_clear_update_mitigation() to separate
statements better. ]
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 51802186158c74a0304f51ab963e7c2b3a2b046f upstream
Processor MMIO Stale Data is a class of vulnerabilities that may
expose data after an MMIO operation. For more details please refer to
Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst
Add the Processor MMIO Stale Data bug enumeration. A microcode update
adds new bits to the MSR IA32_ARCH_CAPABILITIES, define them.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 5898b43af954b83c4a4ee4ab85c4dbafa395822a ]
The set_memory_uc() approach doesn't work well in all cases.
As Dan pointed out when "The VMM unmapped the bad page from
guest physical space and passed the machine check to the guest."
"The guest gets virtual #MC on an access to that page. When
the guest tries to do set_memory_uc() and instructs cpa_flush()
to do clean caches that results in taking another fault / exception
perhaps because the VMM unmapped the page from the guest."
Since the driver has special knowledge to handle NP or UC,
mark the poisoned page with NP and let driver handle it when
it comes down to repair.
Please refer to discussions here for more details.
https://lore.kernel.org/all/CAPcyv4hrXPb1tASBZUg-GgdVs0OOFKXMXLiHmktg_kFi7YBMyQ@mail.gmail.com/
Now since poisoned page is marked as not-present, in order to
avoid writing to a not-present page and trigger kernel Oops,
also fix pmem_do_write().
Fixes: 284ce4011ba6 ("x86/memory_failure: Introduce {set, clear}_mce_nospec()")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/165272615484.103830.2563950688772226611.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 12441ccdf5e2f5a01a46e344976cbbd3d46845c9 ]
__setup() handlers should return 1 to obsolete_checksetup() in
init/main.c to indicate that the boot option has been handled. A return
of 0 causes the boot option/value to be listed as an Unknown kernel
parameter and added to init's (limited) argument (no '=') or environment
(with '=') strings. So return 1 from these x86 __setup handlers.
Examples:
Unknown kernel command line parameters "apicpmtimer
BOOT_IMAGE=/boot/bzImage-517rc8 vdso=1 ring3mwait=disable", will be
passed to user space.
Run /sbin/init as init process
with arguments:
/sbin/init
apicpmtimer
with environment:
HOME=/
TERM=linux
BOOT_IMAGE=/boot/bzImage-517rc8
vdso=1
ring3mwait=disable
Fixes: 2aae950b21e4 ("x86_64: Add vDSO for x86-64 with gettimeofday/clock_gettime/getcpu")
Fixes: 77b52b4c5c66 ("x86: add "debugpat" boot option")
Fixes: e16fd002afe2 ("x86/cpufeature: Enable RING3MWAIT for Knights Landing")
Fixes: b8ce33590687 ("x86_64: convert to clock events")
Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Link: https://lore.kernel.org/r/20220314012725.26661-1-rdunlap@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 0c9782e204d3cc5625b9e8bf4e8625d38dfe0139 upstream.
When the system runs out of enclave memory, SGX can reclaim EPC pages
by swapping to normal RAM. These backing pages are allocated via a
per-enclave shared memory area. Since SGX allows unlimited over
commit on EPC memory, the reclaimer thread can allocate a large
number of backing RAM pages in response to EPC memory pressure.
When the shared memory backing RAM allocation occurs during
the reclaimer thread context, the shared memory is charged to
the root memory control group, and the shmem usage of the enclave
is not properly accounted for, making cgroups ineffective at
limiting the amount of RAM an enclave can consume.
For example, when using a cgroup to launch a set of test
enclaves, the kernel does not properly account for 50% - 75% of
shmem page allocations on average. In the worst case, when
nearly all allocations occur during the reclaimer thread, the
kernel accounts less than a percent of the amount of shmem used
by the enclave's cgroup to the correct cgroup.
SGX stores a list of mm_structs that are associated with
an enclave. Pick one of them during reclaim and charge that
mm's memcg with the shmem allocation. The one that gets picked
is arbitrary, but this list almost always only has one mm. The
cases where there is more than one mm with different memcg's
are not worth considering.
Create a new function - sgx_encl_alloc_backing(). This function
is used whenever a new backing storage page needs to be
allocated. Previously the same function was used for page
allocation as well as retrieving a previously allocated page.
Prior to backing page allocation, if there is a mm_struct associated
with the enclave that is requesting the allocation, it is set
as the active memory control group.
[ dhansen: - fix merge conflict with ELDU fixes
- check against actual ksgxd_tsk, not ->mm ]
Cc: stable@vger.kernel.org
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lkml.kernel.org/r/20220520174248.4918-1-kristen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e5f28623ceb103e13fc3d7bd45edf9818b227fd0 upstream.
In mce_threshold_create_device(), if threshold_create_bank() fails, the
previously allocated threshold banks array @bp will be leaked because
the call to mce_threshold_remove_device() will not free it.
This happens because mce_threshold_remove_device() fetches the pointer
through the threshold_banks per-CPU variable but bp is written there
only after the bank creation is successful, and not before, when
threshold_create_bank() fails.
Add a helper which unwinds all the bank creation work previously done
and pass into it the previously allocated threshold banks array for
freeing.
[ bp: Massage. ]
Fixes: 6458de97fc15 ("x86/mce/amd: Straighten CPU hotplug path")
Co-developed-by: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>
Signed-off-by: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>
Co-developed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220329104705.65256-3-ammarfaizi2@gnuweeb.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e3a3bbe3e99de73043a1d32d36cf4d211dc58c7e upstream.
A PCMD (Paging Crypto MetaData) page contains the PCMD
structures of enclave pages that have been encrypted and
moved to the shmem backing store. When all enclave pages
sharing a PCMD page are loaded in the enclave, there is no
need for the PCMD page and it can be truncated from the
backing store.
A few issues appeared around the truncation of PCMD pages. The
known issues have been addressed but the PCMD handling code could
be made more robust by loudly complaining if any new issue appears
in this area.
Add a check that will complain with a warning if the PCMD page is not
actually empty after it has been truncated. There should never be data
in the PCMD page at this point since it is was just checked to be empty
and truncated with enclave mutex held and is updated with the
enclave mutex held.
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Haitao Huang <haitao.huang@intel.com>
Link: https://lkml.kernel.org/r/6495120fed43fafc1496d09dd23df922b9a32709.1652389823.git.reinette.chatre@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit af117837ceb9a78e995804ade4726ad2c2c8981f upstream.
Haitao reported encountering a WARN triggered by the ENCLS[ELDU]
instruction faulting with a #GP.
The WARN is encountered when the reclaimer evicts a range of
pages from the enclave when the same pages are faulted back right away.
Consider two enclave pages (ENCLAVE_A and ENCLAVE_B)
sharing a PCMD page (PCMD_AB). ENCLAVE_A is in the
enclave memory and ENCLAVE_B is in the backing store. PCMD_AB contains
just one entry, that of ENCLAVE_B.
Scenario proceeds where ENCLAVE_A is being evicted from the enclave
while ENCLAVE_B is faulted in.
sgx_reclaim_pages() {
...
/*
* Reclaim ENCLAVE_A
*/
mutex_lock(&encl->lock);
/*
* Get a reference to ENCLAVE_A's
* shmem page where enclave page
* encrypted data will be stored
* as well as a reference to the
* enclave page's PCMD data page,
* PCMD_AB.
* Release mutex before writing
* any data to the shmem pages.
*/
sgx_encl_get_backing(...);
encl_page->desc |= SGX_ENCL_PAGE_BEING_RECLAIMED;
mutex_unlock(&encl->lock);
/*
* Fault ENCLAVE_B
*/
sgx_vma_fault() {
mutex_lock(&encl->lock);
/*
* Get reference to
* ENCLAVE_B's shmem page
* as well as PCMD_AB.
*/
sgx_encl_get_backing(...)
/*
* Load page back into
* enclave via ELDU.
*/
/*
* Release reference to
* ENCLAVE_B' shmem page and
* PCMD_AB.
*/
sgx_encl_put_backing(...);
/*
* PCMD_AB is found empty so
* it and ENCLAVE_B's shmem page
* are truncated.
*/
/* Truncate ENCLAVE_B backing page */
sgx_encl_truncate_backing_page();
/* Truncate PCMD_AB */
sgx_encl_truncate_backing_page();
mutex_unlock(&encl->lock);
...
}
mutex_lock(&encl->lock);
encl_page->desc &=
~SGX_ENCL_PAGE_BEING_RECLAIMED;
/*
* Write encrypted contents of
* ENCLAVE_A to ENCLAVE_A shmem
* page and its PCMD data to
* PCMD_AB.
*/
sgx_encl_put_backing(...)
/*
* Reference to PCMD_AB is
* dropped and it is truncated.
* ENCLAVE_A's PCMD data is lost.
*/
mutex_unlock(&encl->lock);
}
What happens next depends on whether it is ENCLAVE_A being faulted
in or ENCLAVE_B being evicted - but both end up with ENCLS[ELDU] faulting
with a #GP.
If ENCLAVE_A is faulted then at the time sgx_encl_get_backing() is called
a new PCMD page is allocated and providing the empty PCMD data for
ENCLAVE_A would cause ENCLS[ELDU] to #GP
If ENCLAVE_B is evicted first then a new PCMD_AB would be allocated by the
reclaimer but later when ENCLAVE_A is faulted the ENCLS[ELDU] instruction
would #GP during its checks of the PCMD value and the WARN would be
encountered.
Noting that the reclaimer sets SGX_ENCL_PAGE_BEING_RECLAIMED at the time
it obtains a reference to the backing store pages of an enclave page it
is in the process of reclaiming, fix the race by only truncating the PCMD
page after ensuring that no page sharing the PCMD page is in the process
of being reclaimed.
Cc: stable@vger.kernel.org
Fixes: 08999b2489b4 ("x86/sgx: Free backing memory after faulting the enclave page")
Reported-by: Haitao Huang <haitao.huang@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Haitao Huang <haitao.huang@intel.com>
Link: https://lkml.kernel.org/r/ed20a5db516aa813873268e125680041ae11dfcf.1652389823.git.reinette.chatre@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 0e4e729a830c1e7f31d3b3fbf8feb355a402b117 upstream.
Haitao reported encountering a WARN triggered by the ENCLS[ELDU]
instruction faulting with a #GP.
The WARN is encountered when the reclaimer evicts a range of
pages from the enclave when the same pages are faulted back
right away.
The SGX backing storage is accessed on two paths: when there
are insufficient free pages in the EPC the reclaimer works
to move enclave pages to the backing storage and as enclaves
access pages that have been moved to the backing storage
they are retrieved from there as part of page fault handling.
An oversubscribed SGX system will often run the reclaimer and
page fault handler concurrently and needs to ensure that the
backing store is accessed safely between the reclaimer and
the page fault handler. This is not the case because the
reclaimer accesses the backing store without the enclave mutex
while the page fault handler accesses the backing store with
the enclave mutex.
Consider the scenario where a page is faulted while a page sharing
a PCMD page with the faulted page is being reclaimed. The
consequence is a race between the reclaimer and page fault
handler, the reclaimer attempting to access a PCMD at the
same time it is truncated by the page fault handler. This
could result in lost PCMD data. Data may still be
lost if the reclaimer wins the race, this is addressed in
the following patch.
The reclaimer accesses pages from the backing storage without
holding the enclave mutex and runs the risk of concurrently
accessing the backing storage with the page fault handler that
does access the backing storage with the enclave mutex held.
In the scenario below a PCMD page is truncated from the backing
store after all its pages have been loaded in to the enclave
at the same time the PCMD page is loaded from the backing store
when one of its pages are reclaimed:
sgx_reclaim_pages() { sgx_vma_fault() {
...
mutex_lock(&encl->lock);
...
__sgx_encl_eldu() {
...
if (pcmd_page_empty) {
/*
* EPC page being reclaimed /*
* shares a PCMD page with an * PCMD page truncated
* enclave page that is being * while requested from
* faulted in. * reclaimer.
*/ */
sgx_encl_get_backing() <----------> sgx_encl_truncate_backing_page()
}
mutex_unlock(&encl->lock);
} }
In this scenario there is a race between the reclaimer and the page fault
handler when the reclaimer attempts to get access to the same PCMD page
that is being truncated. This could result in the reclaimer writing to
the PCMD page that is then truncated, causing the PCMD data to be lost,
or in a new PCMD page being allocated. The lost PCMD data may still occur
after protecting the backing store access with the mutex - this is fixed
in the next patch. By ensuring the backing store is accessed with the mutex
held the enclave page state can be made accurate with the
SGX_ENCL_PAGE_BEING_RECLAIMED flag accurately reflecting that a page
is in the process of being reclaimed.
Consistently protect the reclaimer's backing store access with the
enclave's mutex to ensure that it can safely run concurrently with the
page fault handler.
Cc: stable@vger.kernel.org
Fixes: 1728ab54b4be ("x86/sgx: Add a page reclaimer")
Reported-by: Haitao Huang <haitao.huang@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Haitao Huang <haitao.huang@intel.com>
Link: https://lkml.kernel.org/r/fa2e04c561a8555bfe1f4e7adc37d60efc77387b.1652389823.git.reinette.chatre@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2154e1c11b7080aa19f47160bd26b6f39bbd7824 upstream.
Recent commit 08999b2489b4 ("x86/sgx: Free backing memory
after faulting the enclave page") expanded __sgx_encl_eldu()
to clear an enclave page's PCMD (Paging Crypto MetaData)
from the PCMD page in the backing store after the enclave
page is restored to the enclave.
Since the PCMD page in the backing store is modified the page
should be marked as dirty to ensure the modified data is retained.
Cc: stable@vger.kernel.org
Fixes: 08999b2489b4 ("x86/sgx: Free backing memory after faulting the enclave page")
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Haitao Huang <haitao.huang@intel.com>
Link: https://lkml.kernel.org/r/00cd2ac480db01058d112e347b32599c1a806bc4.1652389823.git.reinette.chatre@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6bd429643cc265e94a9d19839c771bcc5d008fa8 upstream.
SGX uses shmem backing storage to store encrypted enclave pages
and their crypto metadata when enclave pages are moved out of
enclave memory. Two shmem backing storage pages are associated with
each enclave page - one backing page to contain the encrypted
enclave page data and one backing page (shared by a few
enclave pages) to contain the crypto metadata used by the
processor to verify the enclave page when it is loaded back into
the enclave.
sgx_encl_put_backing() is used to release references to the
backing storage and, optionally, mark both backing store pages
as dirty.
Managing references and dirty status together in this way results
in both backing store pages marked as dirty, even if only one of
the backing store pages are changed.
Additionally, waiting until the page reference is dropped to set
the page dirty risks a race with the page fault handler that
may load outdated data into the enclave when a page is faulted
right after it is reclaimed.
Consider what happens if the reclaimer writes a page to the backing
store and the page is immediately faulted back, before the reclaimer
is able to set the dirty bit of the page:
sgx_reclaim_pages() { sgx_vma_fault() {
...
sgx_encl_get_backing();
... ...
sgx_reclaimer_write() {
mutex_lock(&encl->lock);
/* Write data to backing store */
mutex_unlock(&encl->lock);
}
mutex_lock(&encl->lock);
__sgx_encl_eldu() {
...
/*
* Enclave backing store
* page not released
* nor marked dirty -
* contents may not be
* up to date.
*/
sgx_encl_get_backing();
...
/*
* Enclave data restored
* from backing store
* and PCMD pages that
* are not up to date.
* ENCLS[ELDU] faults
* because of MAC or PCMD
* checking failure.
*/
sgx_encl_put_backing();
}
...
/* set page dirty */
sgx_encl_put_backing();
...
mutex_unlock(&encl->lock);
} }
Remove the option to sgx_encl_put_backing() to set the backing
pages as dirty and set the needed pages as dirty right after
receiving important data while enclave mutex is held. This ensures that
the page fault handler can get up to date data from a page and prepares
the code for a following change where only one of the backing pages
need to be marked as dirty.
Cc: stable@vger.kernel.org
Fixes: 1728ab54b4be ("x86/sgx: Add a page reclaimer")
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Haitao Huang <haitao.huang@intel.com>
Link: https://lore.kernel.org/linux-sgx/8922e48f-6646-c7cc-6393-7c78dcf23d23@intel.com/
Link: https://lkml.kernel.org/r/fa9f98986923f43e72ef4c6702a50b2a0b3c42e3.1652389823.git.reinette.chatre@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
When resuming from system sleep state, restore_processor_state()
restores the boot CPU MSRs. These MSRs could be emulated by microcode.
If microcode is not loaded yet, writing to emulated MSRs leads to
unchecked MSR access error:
...
PM: Calling lapic_suspend+0x0/0x210
unchecked MSR access error: WRMSR to 0x10f (tried to write 0x0...0) at rIP: ... (native_write_msr)
Call Trace:
<TASK>
? restore_processor_state
x86_acpi_suspend_lowlevel
acpi_suspend_enter
suspend_devices_and_enter
pm_suspend.cold
state_store
kobj_attr_store
sysfs_kf_write
kernfs_fop_write_iter
new_sync_write
vfs_write
ksys_write
__x64_sys_write
do_syscall_64
entry_SYSCALL_64_after_hwframe
RIP: 0033:0x7fda13c260a7
To ensure microcode emulated MSRs are available for restoration, load
the microcode on the boot CPU before restoring these MSRs.
[ Pawan: write commit message and productize it. ]
Fixes: e2a1256b17b1 ("x86/speculation: Restore speculation related MSRs during S3 resume")
Reported-by: Kyle D. Pelton <kyle.d.pelton@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Tested-by: Kyle D. Pelton <kyle.d.pelton@intel.com>
Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215841
Link: https://lore.kernel.org/r/4350dfbf785cd482d3fafa72b2b49c83102df3ce.1650386317.git.pawan.kumar.gupta@linux.intel.com
|
|
A microcode update on some Intel processors causes all TSX transactions
to always abort by default[*]. Microcode also added functionality to
re-enable TSX for development purposes. With this microcode loaded, if
tsx=on was passed on the cmdline, and TSX development mode was already
enabled before the kernel boot, it may make the system vulnerable to TSX
Asynchronous Abort (TAA).
To be on safer side, unconditionally disable TSX development mode during
boot. If a viable use case appears, this can be revisited later.
[*]: Intel TSX Disable Update for Selected Processors, doc ID: 643557
[ bp: Drop unstable web link, massage heavily. ]
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Neelima Krishnan <neelima.krishnan@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/347bd844da3a333a9793c6687d4e4eb3b2419a3e.1646943780.git.pawan.kumar.gupta@linux.intel.com
|
|
tsx_clear_cpuid() uses MSR_TSX_FORCE_ABORT to clear CPUID.RTM and
CPUID.HLE. Not all CPUs support MSR_TSX_FORCE_ABORT, alternatively use
MSR_IA32_TSX_CTRL when supported.
[ bp: Document how and why TSX gets disabled. ]
Fixes: 293649307ef9 ("x86/tsx: Clear CPUID bits when TSX always force aborts")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Neelima Krishnan <neelima.krishnan@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/5b323e77e251a9c8bcdda498c5cc0095be1e1d3c.1646943780.git.pawan.kumar.gupta@linux.intel.com
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here is the set of driver core changes for 5.18-rc1.
Not much here, primarily it was a bunch of cleanups and small updates:
- kobj_type cleanups for default_groups
- documentation updates
- firmware loader minor changes
- component common helper added and take advantage of it in many
drivers (the largest part of this pull request).
All of these have been in linux-next for a while with no reported
problems"
* tag 'driver-core-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (54 commits)
Documentation: update stable review cycle documentation
drivers/base/dd.c : Remove the initial value of the global variable
Documentation: update stable tree link
Documentation: add link to stable release candidate tree
devres: fix typos in comments
Documentation: add note block surrounding security patch note
samples/kobject: Use sysfs_emit instead of sprintf
base: soc: Make soc_device_match() simpler and easier to read
driver core: dd: fix return value of __setup handler
driver core: Refactor sysfs and drv/bus remove hooks
driver core: Refactor multiple copies of device cleanup
scripts: get_abi.pl: Fix typo in help message
kernfs: fix typos in comments
kernfs: remove unneeded #if 0 guard
ALSA: hda/realtek: Make use of the helper component_compare_dev_name
video: omapfb: dss: Make use of the helper component_compare_dev
power: supply: ab8500: Make use of the helper component_compare_dev
ASoC: codecs: wcd938x: Make use of the helper component_compare/release_of
iommu/mediatek: Make use of the helper component_compare/release_of
drm: of: Make use of the helper component_release_of
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 CET-IBT (Control-Flow-Integrity) support from Peter Zijlstra:
"Add support for Intel CET-IBT, available since Tigerlake (11th gen),
which is a coarse grained, hardware based, forward edge
Control-Flow-Integrity mechanism where any indirect CALL/JMP must
target an ENDBR instruction or suffer #CP.
Additionally, since Alderlake (12th gen)/Sapphire-Rapids, speculation
is limited to 2 instructions (and typically fewer) on branch targets
not starting with ENDBR. CET-IBT also limits speculation of the next
sequential instruction after the indirect CALL/JMP [1].
CET-IBT is fundamentally incompatible with retpolines, but provides,
as described above, speculation limits itself"
[1] https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/technical-documentation/branch-history-injection.html
* tag 'x86_core_for_5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
kvm/emulate: Fix SETcc emulation for ENDBR
x86/Kconfig: Only allow CONFIG_X86_KERNEL_IBT with ld.lld >= 14.0.0
x86/Kconfig: Only enable CONFIG_CC_HAS_IBT for clang >= 14.0.0
kbuild: Fixup the IBT kbuild changes
x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy
x86: Remove toolchain check for X32 ABI capability
x86/alternative: Use .ibt_endbr_seal to seal indirect calls
objtool: Find unused ENDBR instructions
objtool: Validate IBT assumptions
objtool: Add IBT/ENDBR decoding
objtool: Read the NOENDBR annotation
x86: Annotate idtentry_df()
x86,objtool: Move the ASM_REACHABLE annotation to objtool.h
x86: Annotate call_on_stack()
objtool: Rework ASM_REACHABLE
x86: Mark __invalid_creds() __noreturn
exit: Mark do_group_exit() __noreturn
x86: Mark stop_this_cpu() __noreturn
objtool: Ignore extra-symbol code
objtool: Rename --duplicate to --lto
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RAS updates from Borislav Petkov:
- More noinstr fixes
- Add an erratum workaround for Intel CPUs which, in certain
circumstances, end up consuming an unrelated uncorrectable memory
error when using fast string copy insns
- Remove the MCE tolerance level control as it is not really needed or
used anymore
* tag 'ras_core_for_v5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mce: Remove the tolerance level control
x86/mce: Work around an erratum on fast string copy instructions
x86/mce: Use arch atomic and bit helpers
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git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv updates from Wei Liu:
"Minor patches from various people"
* tag 'hyperv-next-signed-20220322' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
x86/hyperv: Output host build info as normal Windows version number
hv_balloon: rate-limit "Unhandled message" warning
drivers: hv: log when enabling crash_kexec_post_notifiers
hv_utils: Add comment about max VMbus packet size in VSS driver
Drivers: hv: Compare cpumasks and not their weights in init_vp_index()
Drivers: hv: Rename 'alloced' to 'allocated'
Drivers: hv: vmbus: Use struct_size() helper in kmalloc()
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Merge updates from Andrew Morton:
- A few misc subsystems: kthread, scripts, ntfs, ocfs2, block, and vfs
- Most the MM patches which precede the patches in Willy's tree: kasan,
pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap,
sparsemem, vmalloc, pagealloc, memory-failure, mlock, hugetlb,
userfaultfd, vmscan, compaction, mempolicy, oom-kill, migration, thp,
cma, autonuma, psi, ksm, page-poison, madvise, memory-hotplug, rmap,
zswap, uaccess, ioremap, highmem, cleanups, kfence, hmm, and damon.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (227 commits)
mm/damon/sysfs: remove repeat container_of() in damon_sysfs_kdamond_release()
Docs/ABI/testing: add DAMON sysfs interface ABI document
Docs/admin-guide/mm/damon/usage: document DAMON sysfs interface
selftests/damon: add a test for DAMON sysfs interface
mm/damon/sysfs: support DAMOS stats
mm/damon/sysfs: support DAMOS watermarks
mm/damon/sysfs: support schemes prioritization
mm/damon/sysfs: support DAMOS quotas
mm/damon/sysfs: support DAMON-based Operation Schemes
mm/damon/sysfs: support the physical address space monitoring
mm/damon/sysfs: link DAMON for virtual address spaces monitoring
mm/damon: implement a minimal stub for sysfs-based DAMON interface
mm/damon/core: add number of each enum type values
mm/damon/core: allow non-exclusive DAMON start/stop
Docs/damon: update outdated term 'regions update interval'
Docs/vm/damon/design: update DAMON-Idle Page Tracking interference handling
Docs/vm/damon: call low level monitoring primitives the operations
mm/damon: remove unnecessary CONFIG_DAMON option
mm/damon/paddr,vaddr: remove damon_{p,v}a_{target_valid,set_operations}()
mm/damon/dbgfs-test: fix is_target_id() change
...
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When the hwpoison page meets the filter conditions, it should not be
regarded as successful memory_failure() processing for mce handler, but
should return a distinct value, otherwise mce handler regards the error
page has been identified and isolated, which may lead to calling
set_mce_nospec() to change page attribute, etc.
Here memory_failure() return -EOPNOTSUPP to indicate that the error
event is filtered, mce handler should not take any action for this
situation and hwpoison injector should treat as correct.
Link: https://lkml.kernel.org/r/20220223082135.2769649-1-luofei@unicloud.com
Signed-off-by: luofei <luofei@unicloud.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
- Cleanups for SCHED_DEADLINE
- Tracing updates/fixes
- CPU Accounting fixes
- First wave of changes to optimize the overhead of the scheduler
build, from the fast-headers tree - including placeholder *_api.h
headers for later header split-ups.
- Preempt-dynamic using static_branch() for ARM64
- Isolation housekeeping mask rework; preperatory for further changes
- NUMA-balancing: deal with CPU-less nodes
- NUMA-balancing: tune systems that have multiple LLC cache domains per
node (eg. AMD)
- Updates to RSEQ UAPI in preparation for glibc usage
- Lots of RSEQ/selftests, for same
- Add Suren as PSI co-maintainer
* tag 'sched-core-2022-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (81 commits)
sched/headers: ARM needs asm/paravirt_api_clock.h too
sched/numa: Fix boot crash on arm64 systems
headers/prep: Fix header to build standalone: <linux/psi.h>
sched/headers: Only include <linux/entry-common.h> when CONFIG_GENERIC_ENTRY=y
cgroup: Fix suspicious rcu_dereference_check() usage warning
sched/preempt: Tell about PREEMPT_DYNAMIC on kernel headers
sched/topology: Remove redundant variable and fix incorrect type in build_sched_domains
sched/deadline,rt: Remove unused parameter from pick_next_[rt|dl]_entity()
sched/deadline,rt: Remove unused functions for !CONFIG_SMP
sched/deadline: Use __node_2_[pdl|dle]() and rb_first_cached() consistently
sched/deadline: Merge dl_task_can_attach() and dl_cpu_busy()
sched/deadline: Move bandwidth mgmt and reclaim functions into sched class source file
sched/deadline: Remove unused def_dl_bandwidth
sched/tracing: Report TASK_RTLOCK_WAIT tasks as TASK_UNINTERRUPTIBLE
sched/tracing: Don't re-read p->state when emitting sched_switch event
sched/rt: Plug rt_mutex_setprio() vs push_rt_task() race
sched/cpuacct: Remove redundant RCU read lock
sched/cpuacct: Optimize away RCU read lock
sched/cpuacct: Fix charge percpu cpuusage
sched/headers: Reorganize, clean up and optimize kernel/sched/sched.h dependencies
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 confidential computing updates from Borislav Petkov:
- Add shared confidential computing code which will be used by both
vendors instead of proliferating home-grown solutions for
technologies (SEV/SNP and TDX) which are pretty similar
* tag 'x86_cc_for_v5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/cpa: Generalize __set_memory_enc_pgtable()
x86/coco: Add API to handle encryption mask
x86/coco: Explicitly declare type of confidential computing platform
x86/cc: Move arch/x86/{kernel/cc_platform.c => coco/core.c}
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu feature updates from Borislav Petkov:
- Merge the AMD and Intel PPIN code into a shared one by both vendors.
Add the PPIN number to sysfs so that sockets can be identified when
replacement is needed
- Minor fixes and cleanups
* tag 'x86_cpu_for_v5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Clear SME feature flag when not in use
x86/cpufeatures: Put the AMX macros in the word 18 block
topology/sysfs: Add PPIN in sysfs under cpu topology
topology/sysfs: Add format parameter to macro defining "show" functions for proc
x86/cpu: Read/save PPIN MSR during initialization
x86/cpu: X86_FEATURE_INTEL_PPIN finally has a CPUID bit
x86/cpu: Merge Intel and AMD ppin_init() functions
x86/CPU/AMD: Use default_groups in kobj_type
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Conflicts:
arch/x86/include/asm/cpufeatures.h
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Assume firmware isn't IBT clean and disable it across calls.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154318.759989383@infradead.org
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Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154318.641454603@infradead.org
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The bits required to make the hardware go.. Of note is that, provided
the syscall entry points are covered with ENDBR, #CP doesn't need to
be an IST because we'll never hit the syscall gap.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154318.582331711@infradead.org
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
- Free shmem backing storage for SGX enclave pages when those are
swapped back into EPC memory
- Prevent do_int3() from being kprobed, to avoid recursion
- Remap setup_data and setup_indirect structures properly when
accessing their members
- Correct the alternatives patching order for modules too
* tag 'x86_urgent_for_v5.17_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sgx: Free backing memory after faulting the enclave page
x86/traps: Mark do_int3() NOKPROBE_SYMBOL
x86/boot: Add setup_indirect support in early_memremap_is_setup_data()
x86/boot: Fix memremap of setup_indirect structures
x86/module: Fix the paravirt vs alternative order
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There is a limited amount of SGX memory (EPC) on each system. When that
memory is used up, SGX has its own swapping mechanism which is similar
in concept but totally separate from the core mm/* code. Instead of
swapping to disk, SGX swaps from EPC to normal RAM. That normal RAM
comes from a shared memory pseudo-file and can itself be swapped by the
core mm code. There is a hierarchy like this:
EPC <-> shmem <-> disk
After data is swapped back in from shmem to EPC, the shmem backing
storage needs to be freed. Currently, the backing shmem is not freed.
This effectively wastes the shmem while the enclave is running. The
memory is recovered when the enclave is destroyed and the backing
storage freed.
Sort this out by freeing memory with shmem_truncate_range(), as soon as
a page is faulted back to the EPC. In addition, free the memory for
PCMD pages as soon as all PCMD's in a page have been marked as unused
by zeroing its contents.
Cc: stable@vger.kernel.org
Fixes: 1728ab54b4be ("x86/sgx: Add a page reclaimer")
Reported-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20220303223859.273187-1-jarkko@kernel.org
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Hyper-V provides host version number information that is output in
text form by a Linux guest when it boots. For whatever reason, the
formatting has historically been non-standard. Change it to output
in normal Windows version format for better readability.
Similar code for ARM64 guests already outputs in normal Windows
version format.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1646767364-2234-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
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The commit
44a3918c8245 ("x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting")
added a warning for the "eIBRS + unprivileged eBPF" combination, which
has been shown to be vulnerable against Spectre v2 BHB-based attacks.
However, there's no warning about the "eIBRS + LFENCE retpoline +
unprivileged eBPF" combo. The LFENCE adds more protection by shortening
the speculation window after a mispredicted branch. That makes an attack
significantly more difficult, even with unprivileged eBPF. So at least
for now the logic doesn't warn about that combination.
But if you then add SMT into the mix, the SMT attack angle weakens the
effectiveness of the LFENCE considerably.
So extend the "eIBRS + unprivileged eBPF" warning to also include the
"eIBRS + LFENCE + unprivileged eBPF + SMT" case.
[ bp: Massage commit message. ]
Suggested-by: Alyssa Milburn <alyssa.milburn@linux.intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
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With:
f8a66d608a3e ("x86,bugs: Unconditionally allow spectre_v2=retpoline,amd")
it became possible to enable the LFENCE "retpoline" on Intel. However,
Intel doesn't recommend it, as it has some weaknesses compared to
retpoline.
Now AMD doesn't recommend it either.
It can still be left available as a cmdline option. It's faster than
retpoline but is weaker in certain scenarios -- particularly SMT, but
even non-SMT may be vulnerable in some cases.
So just unconditionally warn if the user requests it on the cmdline.
[ bp: Massage commit message. ]
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
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AMD retpoline may be susceptible to speculation. The speculation
execution window for an incorrect indirect branch prediction using
LFENCE/JMP sequence may potentially be large enough to allow
exploitation using Spectre V2.
By default, don't use retpoline,lfence on AMD. Instead, use the
generic retpoline.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
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We need the driver core fix in here as well for future changes.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The kernel derives the confidential computing platform
type it is running as from sme_me_mask on AMD or by using
hv_is_isolation_supported() on HyperV isolation VMs. This detection
process will be more complicated as more platforms get added.
Declare a confidential computing vendor variable explicitly and set it
via cc_set_vendor() on the respective platform.
[ bp: Massage commit message, fixup HyperV check. ]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20220222185740.26228-4-kirill.shutemov@linux.intel.com
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There is no need to have struct kernfs_root be part of kernfs.h for
the whole kernel to see and poke around it. Move it internal to kernfs
code and provide a helper function, kernfs_root_to_node(), to handle the
one field that kernfs users were directly accessing from the structure.
Cc: Imran Khan <imran.f.khan@oracle.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220222070713.3517679-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This is pretty much unused and not really useful. What is more, all
relevant MCA hardware has recoverable machine checks support so there's
no real need to tweak MCA tolerance levels in order to *maybe* extend
machine lifetime.
So rip it out.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/YcDq8PxvKtTENl/e@zn.tnic
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New conflicts in sched/core due to the following upstream fixes:
44585f7bc0cb ("psi: fix "defined but not used" warnings when CONFIG_PROC_FS=n")
a06247c6804f ("psi: Fix uaf issue when psi trigger is destroyed while being polled")
Conflicts:
include/linux/psi_types.h
kernel/sched/psi.c
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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reporting
With unprivileged eBPF enabled, eIBRS (without retpoline) is vulnerable
to Spectre v2 BHB-based attacks.
When both are enabled, print a warning message and report it in the
'spectre_v2' sysfs vulnerabilities file.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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Thanks to the chaps at VUsec it is now clear that eIBRS is not
sufficient, therefore allow enabling of retpolines along with eIBRS.
Add spectre_v2=eibrs, spectre_v2=eibrs,lfence and
spectre_v2=eibrs,retpoline options to explicitly pick your preferred
means of mitigation.
Since there's new mitigations there's also user visible changes in
/sys/devices/system/cpu/vulnerabilities/spectre_v2 to reflect these
new mitigations.
[ bp: Massage commit message, trim error messages,
do more precise eIBRS mode checking. ]
Co-developed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Patrick Colp <patrick.colp@oracle.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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The RETPOLINE_AMD name is unfortunate since it isn't necessarily
AMD only, in fact Hygon also uses it. Furthermore it will likely be
sufficient for some Intel processors. Therefore rename the thing to
RETPOLINE_LFENCE to better describe what it is.
Add the spectre_v2=retpoline,lfence option as an alias to
spectre_v2=retpoline,amd to preserve existing setups. However, the output
of /sys/devices/system/cpu/vulnerabilities/spectre_v2 will be changed.
[ bp: Fix typos, massage. ]
Co-developed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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A rare kernel panic scenario can happen when the following conditions
are met due to an erratum on fast string copy instructions:
1) An uncorrected error.
2) That error must be in first cache line of a page.
3) Kernel must execute page_copy from the page immediately before that
page.
The fast string copy instructions ("REP; MOVS*") could consume an
uncorrectable memory error in the cache line _right after_ the desired
region to copy and raise an MCE.
Bit 0 of MSR_IA32_MISC_ENABLE can be cleared to disable fast string
copy and will avoid such spurious machine checks. However, that is less
preferable due to the permanent performance impact. Considering memory
poison is rare, it's desirable to keep fast string copy enabled until an
MCE is seen.
Intel has confirmed the following:
1. The CPU erratum of fast string copy only applies to Skylake,
Cascade Lake and Cooper Lake generations.
Directly return from the MCE handler:
2. Will result in complete execution of the "REP; MOVS*" with no data
loss or corruption.
3. Will not result in another MCE firing on the next poisoned cache line
due to "REP; MOVS*".
4. Will resume execution from a correct point in code.
5. Will result in the same instruction that triggered the MCE firing a
second MCE immediately for any other software recoverable data fetch
errors.
6. Is not safe without disabling the fast string copy, as the next fast
string copy of the same buffer on the same CPU would result in a PANIC
MCE.
This should mitigate the erratum completely with the only caveat that
the fast string copy is disabled on the affected hyper thread thus
performance degradation.
This is still better than the OS crashing on MCEs raised on an
irrelevant process due to "REP; MOVS*' accesses in a kernel context,
e.g., copy_page.
Tested:
Injected errors on 1st cache line of 8 anonymous pages of process
'proc1' and observed MCE consumption from 'proc2' with no panic
(directly returned).
Without the fix, the host panicked within a few minutes on a
random 'proc2' process due to kernel access from copy_page.
[ bp: Fix comment style + touch ups, zap an unlikely(), improve the
quirk function's readability. ]
Signed-off-by: Jue Wang <juew@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20220218013209.2436006-1-juew@google.com
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