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commit eb3515dc99c7c85f4170b50838136b2a193f8012 upstream.
The declaration got placed in the .c file of the caller, but that
causes a warning for the definition:
arch/x86/kernel/cpu/bugs.c:682:6: error: no previous prototype for 'gds_ucode_mitigated' [-Werror=missing-prototypes]
Move it to a header where both sides can observe it instead.
Fixes: 81ac7e5d74174 ("KVM: Add GDS_NO support to KVM")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Cc: stable@kernel.org
Link: https://lore.kernel.org/all/20230809130530.1913368-2-arnd%40kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1b8b1aa90c9c0e825b181b98b8d9e249dc395470 upstream.
Yingcong has noticed that on the 5-level paging machine, VDSO and VVAR
VMAs are placed above the 47-bit border:
8000001a9000-8000001ad000 r--p 00000000 00:00 0 [vvar]
8000001ad000-8000001af000 r-xp 00000000 00:00 0 [vdso]
This might confuse users who are not aware of 5-level paging and expect
all userspace addresses to be under the 47-bit border.
So far problem has only been triggered with ASLR disabled, although it
may also occur with ASLR enabled if the layout is randomized in a just
right way.
The problem happens due to custom placement for the VMAs in the VDSO
code: vdso_addr() tries to place them above the stack and checks the
result against TASK_SIZE_MAX, which is wrong. TASK_SIZE_MAX is set to
the 56-bit border on 5-level paging machines. Use DEFAULT_MAP_WINDOW
instead.
Fixes: b569bab78d8d ("x86/mm: Prepare to expose larger address space to userspace")
Reported-by: Yingcong Wu <yingcong.wu@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20230803151609.22141-1-kirill.shutemov%40linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6dbef74aeb090d6bee7d64ef3fa82ae6fa53f271 upstream.
Commit
522b1d69219d ("x86/cpu/amd: Add a Zenbleed fix")
provided a fix for the Zen2 VZEROUPPER data corruption bug affecting
a range of CPU models, but the AMD Custom APU 0405 found on SteamDeck
was not listed, although it is clearly affected by the vulnerability.
Add this CPU variant to the Zenbleed erratum list, in order to
unconditionally enable the fallback fix until a proper microcode update
is available.
Fixes: 522b1d69219d ("x86/cpu/amd: Add a Zenbleed fix")
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230811203705.1699914-1-cristian.ciocaltea@collabora.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3f649ab728cda8038259d8f14492fe400fbab911 upstream.
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.
In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:
git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
xargs perl -pi -e \
's/\buninitialized_var\(([^\)]+)\)/\1/g;
s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'
drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.
No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.
[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/
Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f9c9987bf52f4e42e940ae217333ebb5a4c3b506 upstream.
Monitoring idletask::thread_info::flags in mwait_play_dead() has been an
obvious choice as all what is needed is a cache line which is not written
by other CPUs.
But there is a use case where a "dead" CPU needs to be brought out of
MWAIT: kexec().
This is required as kexec() can overwrite text, pagetables, stacks and the
monitored cacheline of the original kernel. The latter causes MWAIT to
resume execution which obviously causes havoc on the kexec kernel which
results usually in triple faults.
Use a dedicated per CPU storage to prepare for that.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230615193330.434553750@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-tree-only change.
Due to the way the GDS and SRSO patches flowed into the stable tree, it
was a 50% chance that the merge of the which value GDS and SRSO should
be. Of course, I lost that bet, and chose the opposite of what Linus
chose in commit 64094e7e3118 ("Merge tag 'gds-for-linus-2023-08-01' of
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip")
Fix this up by switching the values to match what is now in Linus's tree
as that is the correct value to mirror.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit fe3e0a13e597c1c8617814bf9b42ab732db5c26e upstream.
Moving the call of fpu__init_cpu() from cpu_init() to start_secondary()
broke Xen PV guests, as those don't call start_secondary() for APs.
Call fpu__init_cpu() in Xen's cpu_bringup(), which is the Xen PV
replacement of start_secondary().
Fixes: b81fac906a8f ("x86/fpu: Move FPU initialization into arch_cpu_finalize_init()")
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230703130032.22916-1-jgross@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 81ac7e5d741742d650b4ed6186c4826c1a0631a7 upstream
Gather Data Sampling (GDS) is a transient execution attack using
gather instructions from the AVX2 and AVX512 extensions. This attack
allows malicious code to infer data that was previously stored in
vector registers. Systems that are not vulnerable to GDS will set the
GDS_NO bit of the IA32_ARCH_CAPABILITIES MSR. This is useful for VM
guests that may think they are on vulnerable systems that are, in
fact, not affected. Guests that are running on affected hosts where
the mitigation is enabled are protected as if they were running
on an unaffected system.
On all hosts that are not affected or that are mitigated, set the
GDS_NO bit.
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 53cf5797f114ba2bd86d23a862302119848eff19 upstream
Gather Data Sampling (GDS) is mitigated in microcode. However, on
systems that haven't received the updated microcode, disabling AVX
can act as a mitigation. Add a Kconfig option that uses the microcode
mitigation if available and disables AVX otherwise. Setting this
option has no effect on systems not affected by GDS. This is the
equivalent of setting gather_data_sampling=force.
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 553a5c03e90a6087e88f8ff878335ef0621536fb upstream
The Gather Data Sampling (GDS) vulnerability allows malicious software
to infer stale data previously stored in vector registers. This may
include sensitive data such as cryptographic keys. GDS is mitigated in
microcode, and systems with up-to-date microcode are protected by
default. However, any affected system that is running with older
microcode will still be vulnerable to GDS attacks.
Since the gather instructions used by the attacker are part of the
AVX2 and AVX512 extensions, disabling these extensions prevents gather
instructions from being executed, thereby mitigating the system from
GDS. Disabling AVX2 is sufficient, but we don't have the granularity
to do this. The XCR0[2] disables AVX, with no option to just disable
AVX2.
Add a kernel parameter gather_data_sampling=force that will enable the
microcode mitigation if available, otherwise it will disable AVX on
affected systems.
This option will be ignored if cmdline mitigations=off.
This is a *big* hammer. It is known to break buggy userspace that
uses incomplete, buggy AVX enumeration. Unfortunately, such userspace
does exist in the wild:
https://www.mail-archive.com/bug-coreutils@gnu.org/msg33046.html
[ dhansen: add some more ominous warnings about disabling AVX ]
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8974eb588283b7d44a7c91fa09fcbaf380339f3a upstream
Gather Data Sampling (GDS) is a hardware vulnerability which allows
unprivileged speculative access to data which was previously stored in
vector registers.
Intel processors that support AVX2 and AVX512 have gather instructions
that fetch non-contiguous data elements from memory. On vulnerable
hardware, when a gather instruction is transiently executed and
encounters a fault, stale data from architectural or internal vector
registers may get transiently stored to the destination vector
register allowing an attacker to infer the stale data using typical
side channel techniques like cache timing attacks.
This mitigation is different from many earlier ones for two reasons.
First, it is enabled by default and a bit must be set to *DISABLE* it.
This is the opposite of normal mitigation polarity. This means GDS can
be mitigated simply by updating microcode and leaving the new control
bit alone.
Second, GDS has a "lock" bit. This lock bit is there because the
mitigation affects the hardware security features KeyLocker and SGX.
It needs to be enabled and *STAY* enabled for these features to be
mitigated against GDS.
The mitigation is enabled in the microcode by default. Disable it by
setting gather_data_sampling=off or by disabling all mitigations with
mitigations=off. The mitigation status can be checked by reading:
/sys/devices/system/cpu/vulnerabilities/gather_data_sampling
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b81fac906a8f9e682e513ddd95697ec7a20878d4 upstream
Initializing the FPU during the early boot process is a pointless
exercise. Early boot is convoluted and fragile enough.
Nothing requires that the FPU is set up early. It has to be initialized
before fork_init() because the task_struct size depends on the FPU register
buffer size.
Move the initialization to arch_cpu_finalize_init() which is the perfect
place to do so.
No functional change.
This allows to remove quite some of the custom early command line parsing,
but that's subject to the next installment.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.902376621@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1703db2b90c91b2eb2d699519fc505fe431dde0e upstream
No point in keeping them around.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.841685728@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1f34bb2a24643e0087652d81078e4f616562738d upstream
Nothing in the call chain requires it
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.783704297@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 439e17576eb47f26b78c5bbc72e344d4206d2327 upstream
Invoke the X86ism mem_encrypt_init() from X86 arch_cpu_finalize_init() and
remove the weak fallback from the core code.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230613224545.670360645@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7c7077a72674402654f3291354720cd73cdf649e upstream
check_bugs() is a dumping ground for finalizing the CPU bringup. Only parts of
it has to do with actual CPU bugs.
Split it apart into arch_cpu_finalize_init() and cpu_select_mitigations().
Fixup the bogus 32bit comments while at it.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230613224545.019583869@linutronix.de
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Upstream commit: 522b1d69219d8f083173819fde04f994aa051a98
Add a fix for the Zen2 VZEROUPPER data corruption bug where under
certain circumstances executing VZEROUPPER can cause register
corruption or leak data.
The optimal fix is through microcode but in the case the proper
microcode revision has not been applied, enable a fallback fix using
a chicken bit.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a32b0f0db3f396f1c9be2fe621e77c09ec3d8e7d upstream.
Do the same as early loading - load on both threads.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20230605141332.25948-1-bp@alien8.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 85d38d5810e285d5aec7fb5283107d1da70c12a9 ]
When booting with "intremap=off" and "x2apic_phys" on the kernel command
line, the physical x2APIC driver ends up being used even when x2APIC
mode is disabled ("intremap=off" disables x2APIC mode). This happens
because the first compound condition check in x2apic_phys_probe() is
false due to x2apic_mode == 0 and so the following one returns true
after default_acpi_madt_oem_check() having already selected the physical
x2APIC driver.
This results in the following panic:
kernel BUG at arch/x86/kernel/apic/io_apic.c:2409!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.4.0-rc2-ver4.1rc2 #2
Hardware name: Dell Inc. PowerEdge R6515/07PXPY, BIOS 2.3.6 07/06/2021
RIP: 0010:setup_IO_APIC+0x9c/0xaf0
Call Trace:
<TASK>
? native_read_msr
apic_intr_mode_init
x86_late_time_init
start_kernel
x86_64_start_reservations
x86_64_start_kernel
secondary_startup_64_no_verify
</TASK>
which is:
setup_IO_APIC:
apic_printk(APIC_VERBOSE, "ENABLING IO-APIC IRQs\n");
for_each_ioapic(ioapic)
BUG_ON(mp_irqdomain_create(ioapic));
Return 0 to denote that x2APIC has not been enabled when probing the
physical x2APIC driver.
[ bp: Massage commit message heavily. ]
Fixes: 9ebd680bd029 ("x86, apic: Use probe routines to simplify apic selection")
Signed-off-by: Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Kishon Vijay Abraham I <kvijayab@amd.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230616212236.1389-1-dheerajkumar.srivastava@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 97b6b9cbba40a21c1d9a344d5c1991f8cfbf136e upstream.
If profile-guided optimization is enabled, the purgatory ends up with
multiple .text sections. This is not supported by kexec and crashes the
system.
Link: https://lkml.kernel.org/r/20230321-kexec_clang16-v7-2-b05c520b7296@chromium.org
Fixes: 930457057abe ("kernel/kexec_file.c: split up __kexec_load_puragory")
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Cc: <stable@vger.kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Rix <trix@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ricardo Ribalda Delgado <ribalda@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit aeb84412037b89e06f45e382f044da6f200e12f8 upstream.
GCC 11 (incorrectly[1]) assumes that literal values cast to (void *)
should be treated like a NULL pointer with an offset, and raises
diagnostics when doing bounds checking under -Warray-bounds. GCC 12
got "smarter" about finding these:
In function 'rdfs8',
inlined from 'vga_recalc_vertical' at /srv/code/arch/x86/boot/video-mode.c:124:29,
inlined from 'set_mode' at /srv/code/arch/x86/boot/video-mode.c:163:3:
/srv/code/arch/x86/boot/boot.h:114:9: warning: array subscript 0 is outside array bounds of 'u8[0]' {aka 'unsigned char[]'} [-Warray-bounds]
114 | asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
| ^~~
This has been solved in other places[2] already by using the recently
added absolute_pointer() macro. Do the same here.
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
[2] https://lore.kernel.org/all/20210912160149.2227137-1-linux@roeck-us.net/
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220227195918.705219-1-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2e4be0d011f21593c6b316806779ba1eba2cd7e0 upstream.
The commit e335bb51cc15 ("x86/unwind: Ensure stack pointer is aligned")
tried to align the stack pointer in show_trace_log_lvl(), otherwise the
"stack < stack_info.end" check can't guarantee that the last read does
not go past the end of the stack.
However, we have the same problem with the initial value of the stack
pointer, it can also be unaligned. So without this patch this trivial
kernel module
#include <linux/module.h>
static int init(void)
{
asm volatile("sub $0x4,%rsp");
dump_stack();
asm volatile("add $0x4,%rsp");
return -EAGAIN;
}
module_init(init);
MODULE_LICENSE("GPL");
crashes the kernel.
Fixes: e335bb51cc15 ("x86/unwind: Ensure stack pointer is aligned")
Signed-off-by: Vernon Lovejoy <vlovejoy@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20230512104232.GA10227@redhat.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ce0b15d11ad837fbacc5356941712218e38a0a83 upstream.
The INVLPG instruction is used to invalidate TLB entries for a
specified virtual address. When PCIDs are enabled, INVLPG is supposed
to invalidate TLB entries for the specified address for both the
current PCID *and* Global entries. (Note: Only kernel mappings set
Global=1.)
Unfortunately, some INVLPG implementations can leave Global
translations unflushed when PCIDs are enabled.
As a workaround, never enable PCIDs on affected processors.
I expect there to eventually be microcode mitigations to replace this
software workaround. However, the exact version numbers where that
will happen are not known today. Once the version numbers are set in
stone, the processor list can be tweaked to only disable PCIDs on
affected processors with affected microcode.
Note: if anyone wants a quick fix that doesn't require patching, just
stick 'nopcid' on your kernel command-line.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 5af507bef93c09a94fb8f058213b489178f4cbe5 ]
arch_dynirq_lower_bound() is invoked by the core interrupt code to
retrieve the lowest possible Linux interrupt number for dynamically
allocated interrupts like MSI.
The x86 implementation uses this to exclude the IO/APIC GSI space.
This works correctly as long as there is an IO/APIC registered, but
returns 0 if not. This has been observed in VMs where the BIOS does
not advertise an IO/APIC.
0 is an invalid interrupt number except for the legacy timer interrupt
on x86. The return value is unchecked in the core code, so it ends up
to allocate interrupt number 0 which is subsequently considered to be
invalid by the caller, e.g. the MSI allocation code.
The function has already a check for 0 in the case that an IO/APIC is
registered, as ioapic_dynirq_base is 0 in case of device tree setups.
Consolidate this and zero check for both ioapic_dynirq_base and gsi_top,
which is used in the case that no IO/APIC is registered.
Fixes: 3e5bedc2c258 ("x86/apic: Fix arch_dynirq_lower_bound() bug for DT enabled machines")
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/1679988604-20308-1-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit f96fb2df3eb31ede1b34b0521560967310267750 ]
The detection of atomic update failure in reserve_eilvt_offset() is
not correct. The value returned by atomic_cmpxchg() should be compared
to the old value from the location to be updated.
If these two are the same, then atomic update succeeded and
"eilvt_offsets[offset]" location is updated to "new" in an atomic way.
Otherwise, the atomic update failed and it should be retried with the
value from "eilvt_offsets[offset]" - exactly what atomic_try_cmpxchg()
does in a correct and more optimal way.
Fixes: a68c439b1966c ("apic, x86: Check if EILVT APIC registers are available (AMD only)")
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230227160917.107820-1-ubizjak@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 4984563823f0034d3533854c1b50e729f5191089 upstream.
Extend VMX's nested intercept logic for emulated instructions to handle
"pause" interception, in quotes because KVM's emulator doesn't filter out
NOPs when checking for nested intercepts. Failure to allow emulation of
NOPs results in KVM injecting a #UD into L2 on any NOP that collides with
the emulator's definition of PAUSE, i.e. on all single-byte NOPs.
For PAUSE itself, honor L1's PAUSE-exiting control, but ignore PLE to
avoid unnecessarily injecting a #UD into L2. Per the SDM, the first
execution of PAUSE after VM-Entry is treated as the beginning of a new
loop, i.e. will never trigger a PLE VM-Exit, and so L1 can't expect any
given execution of PAUSE to deterministically exit.
... the processor considers this execution to be the first execution of
PAUSE in a loop. (It also does so for the first execution of PAUSE at
CPL 0 after VM entry.)
All that said, the PLE side of things is currently a moot point, as KVM
doesn't expose PLE to L1.
Note, vmx_check_intercept() is still wildly broken when L1 wants to
intercept an instruction, as KVM injects a #UD instead of synthesizing a
nested VM-Exit. That issue extends far beyond NOP/PAUSE and needs far
more effort to fix, i.e. is a problem for the future.
Fixes: 07721feee46b ("KVM: nVMX: Don't emulate instructions in guest mode")
Cc: Mathias Krause <minipli@grsecurity.net>
Cc: stable@vger.kernel.org
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20230405002359.418138-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 52416ffcf823ee11aa19792715664ab94757f111 upstream.
Purgatory.ro is a standalone binary that is not linked against the rest of
the kernel. Its image is copied into an array that is linked to the
kernel, and from there kexec relocates it wherever it desires.
Unlike the debug info for vmlinux, which can be used for analyzing crash
such info is useless in purgatory.ro. And discarding them can save about
200K space.
Original:
259080 kexec-purgatory.o
Stripped debug info:
29152 kexec-purgatory.o
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Acked-by: Dave Young <dyoung@redhat.com>
Link: https://lore.kernel.org/r/1596433788-3784-1-git-send-email-kernelfans@gmail.com
[Alyssa: fixed for LLVM_IAS=1 by adding -g to AFLAGS_REMOVE_*]
Signed-off-by: Alyssa Ross <hi@alyssa.is>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 112e66017bff7f2837030f34c2bc19501e9212d5 upstream.
The effective values of the guest CR0 and CR4 registers may differ from
those included in the VMCS12. In particular, disabling EPT forces
CR4.PAE=1 and disabling unrestricted guest mode forces CR0.PG=CR0.PE=1.
Therefore, checks on these bits cannot be delegated to the processor
and must be performed by KVM.
Reported-by: Reima ISHII <ishiir@g.ecc.u-tokyo.ac.jp>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[OP: drop CC() macro calls, as tracing is not implemented in 4.19]
[OP: adjust "return -EINVAL" -> "return 1" to match current return logic]
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f195fc1e9715ba826c3b62d58038f760f66a4fe9 upstream.
The AMD [1022:15b8] USB controller loses some internal functional MSI-X
context when transitioning from D0 to D3hot. BIOS normally traps D0->D3hot
and D3hot->D0 transitions so it can save and restore that internal context,
but some firmware in the field can't do this because it fails to clear the
AMD_15B8_RCC_DEV2_EPF0_STRAP2 NO_SOFT_RESET bit.
Clear AMD_15B8_RCC_DEV2_EPF0_STRAP2 NO_SOFT_RESET bit before USB controller
initialization during boot.
Link: https://lore.kernel.org/linux-usb/Y%2Fz9GdHjPyF2rNG3@glanzmann.de/T/#u
Link: https://lore.kernel.org/r/20230329172859.699743-1-Basavaraj.Natikar@amd.com
Reported-by: Thomas Glanzmann <thomas@glanzmann.de>
Tested-by: Thomas Glanzmann <thomas@glanzmann.de>
Signed-off-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 5ed213dd64681f84a01ceaa82fb336cf7d59ddcf ]
Another Lenovo convertable which reports a landscape resolution of
1920x1200 with a pitch of (1920 * 4) bytes, while the actual framebuffer
has a resolution of 1200x1920 with a pitch of (1200 * 4) bytes.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit cbebd68f59f03633469f3ecf9bea99cd6cce3854 upstream.
cmdline_find_option() may fail before doing any initialization of
the buffer array. This may lead to unpredictable results when the same
buffer is used later in calls to strncmp() function. Fix the issue by
returning early if cmdline_find_option() returns an error.
Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.
Fixes: aca20d546214 ("x86/mm: Add support to make use of Secure Memory Encryption")
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20230306160656.14844-1-n.zhandarovich@fintech.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b0563468eeac88ebc70559d52a0b66efc37e4e9d upstream.
AMD Erratum 1386 is summarised as:
XSAVES Instruction May Fail to Save XMM Registers to the Provided
State Save Area
This piece of accidental chronomancy causes the %xmm registers to
occasionally reset back to an older value.
Ignore the XSAVES feature on all AMD Zen1/2 hardware. The XSAVEC
instruction (which works fine) is equivalent on affected parts.
[ bp: Typos, move it into the F17h-specific function. ]
Reported-by: Tavis Ormandy <taviso@gmail.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/20230307174643.1240184-1-andrew.cooper3@citrix.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit e1d447157f232c650e6f32c9fb89ff3d0207c69a ]
Another Lenovo convertable which reports a landscape resolution of
1920x1200 with a pitch of (1920 * 4) bytes, while the actual framebuffer
has a resolution of 1200x1920 with a pitch of (1200 * 4) bytes.
Signed-off-by: Darrell Kavanagh <darrell.kavanagh@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5541992e512de8c9133110809f767bd1b54ee10d ]
The 'syscall' instruction clobbers '%rcx' and '%r11', but they are not
listed in the inline Assembly that performs the syscall instruction.
No real bug is found. It wasn't buggy by luck because '%rcx' and '%r11'
are caller-saved registers, and not used in the functions, and the
functions are never inlined.
Add them to the clobber list for code correctness.
Fixes: f1c2bb8b9964ed31de988910f8b1cfb586d30091 ("um: implement a x86_64 vDSO")
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 6921ed9049bc7457f66c1596c5b78aec0dae4a9d upstream.
When plain IBRS is enabled (not enhanced IBRS), the logic in
spectre_v2_user_select_mitigation() determines that STIBP is not needed.
The IBRS bit implicitly protects against cross-thread branch target
injection. However, with legacy IBRS, the IBRS bit is cleared on
returning to userspace for performance reasons which leaves userspace
threads vulnerable to cross-thread branch target injection against which
STIBP protects.
Exclude IBRS from the spectre_v2_in_ibrs_mode() check to allow for
enabling STIBP (through seccomp/prctl() by default or always-on, if
selected by spectre_v2_user kernel cmdline parameter).
[ bp: Massage. ]
Fixes: 7c693f54c873 ("x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRS")
Reported-by: José Oliveira <joseloliveira11@gmail.com>
Reported-by: Rodrigo Branco <rodrigo@kernelhacking.com>
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230220120127.1975241-1-kpsingh@kernel.org
Link: https://lore.kernel.org/r/20230221184908.2349578-1-kpsingh@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7ff6edf4fef38ab404ee7861f257e28eaaeed35f upstream.
The AMD side of the loader has always claimed to support mixed
steppings. But somewhere along the way, it broke that by assuming that
the cached patch blob is a single one instead of it being one per
*node*.
So turn it into a per-node one so that each node can stash the blob
relevant for it.
[ NB: Fixes tag is not really the exactly correct one but it is good
enough. ]
Fixes: fe055896c040 ("x86/microcode: Merge the early microcode loader")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org> # 2355370cd941 ("x86/microcode/amd: Remove load_microcode_amd()'s bsp parameter")
Cc: <stable@kernel.org> # a5ad92134bd1 ("x86/microcode/AMD: Add a @cpu parameter to the reloading functions")
Link: https://lore.kernel.org/r/20230130161709.11615-4-bp@alien8.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a5ad92134bd153a9ccdcddf09a95b088f36c3cce upstream.
Will be used in a subsequent change.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230130161709.11615-3-bp@alien8.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f1c97a1b4ef709e3f066f82e3ba3108c3b133ae6 upstream.
When arch_prepare_optimized_kprobe calculating jump destination address,
it copies original instructions from jmp-optimized kprobe (see
__recover_optprobed_insn), and calculated based on length of original
instruction.
arch_check_optimized_kprobe does not check KPROBE_FLAG_OPTIMATED when
checking whether jmp-optimized kprobe exists.
As a result, setup_detour_execution may jump to a range that has been
overwritten by jump destination address, resulting in an inval opcode error.
For example, assume that register two kprobes whose addresses are
<func+9> and <func+11> in "func" function.
The original code of "func" function is as follows:
0xffffffff816cb5e9 <+9>: push %r12
0xffffffff816cb5eb <+11>: xor %r12d,%r12d
0xffffffff816cb5ee <+14>: test %rdi,%rdi
0xffffffff816cb5f1 <+17>: setne %r12b
0xffffffff816cb5f5 <+21>: push %rbp
1.Register the kprobe for <func+11>, assume that is kp1, corresponding optimized_kprobe is op1.
After the optimization, "func" code changes to:
0xffffffff816cc079 <+9>: push %r12
0xffffffff816cc07b <+11>: jmp 0xffffffffa0210000
0xffffffff816cc080 <+16>: incl 0xf(%rcx)
0xffffffff816cc083 <+19>: xchg %eax,%ebp
0xffffffff816cc084 <+20>: (bad)
0xffffffff816cc085 <+21>: push %rbp
Now op1->flags == KPROBE_FLAG_OPTIMATED;
2. Register the kprobe for <func+9>, assume that is kp2, corresponding optimized_kprobe is op2.
register_kprobe(kp2)
register_aggr_kprobe
alloc_aggr_kprobe
__prepare_optimized_kprobe
arch_prepare_optimized_kprobe
__recover_optprobed_insn // copy original bytes from kp1->optinsn.copied_insn,
// jump address = <func+14>
3. disable kp1:
disable_kprobe(kp1)
__disable_kprobe
...
if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
ret = disarm_kprobe(orig_p, true) // add op1 in unoptimizing_list, not unoptimized
orig_p->flags |= KPROBE_FLAG_DISABLED; // op1->flags == KPROBE_FLAG_OPTIMATED | KPROBE_FLAG_DISABLED
...
4. unregister kp2
__unregister_kprobe_top
...
if (!kprobe_disabled(ap) && !kprobes_all_disarmed) {
optimize_kprobe(op)
...
if (arch_check_optimized_kprobe(op) < 0) // because op1 has KPROBE_FLAG_DISABLED, here not return
return;
p->kp.flags |= KPROBE_FLAG_OPTIMIZED; // now op2 has KPROBE_FLAG_OPTIMIZED
}
"func" code now is:
0xffffffff816cc079 <+9>: int3
0xffffffff816cc07a <+10>: push %rsp
0xffffffff816cc07b <+11>: jmp 0xffffffffa0210000
0xffffffff816cc080 <+16>: incl 0xf(%rcx)
0xffffffff816cc083 <+19>: xchg %eax,%ebp
0xffffffff816cc084 <+20>: (bad)
0xffffffff816cc085 <+21>: push %rbp
5. if call "func", int3 handler call setup_detour_execution:
if (p->flags & KPROBE_FLAG_OPTIMIZED) {
...
regs->ip = (unsigned long)op->optinsn.insn + TMPL_END_IDX;
...
}
The code for the destination address is
0xffffffffa021072c: push %r12
0xffffffffa021072e: xor %r12d,%r12d
0xffffffffa0210731: jmp 0xffffffff816cb5ee <func+14>
However, <func+14> is not a valid start instruction address. As a result, an error occurs.
Link: https://lore.kernel.org/all/20230216034247.32348-3-yangjihong1@huawei.com/
Fixes: f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Cc: stable@vger.kernel.org
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 868a6fc0ca2407622d2833adefe1c4d284766c4c upstream.
Since the following commit:
commit f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code")
modified the update timing of the KPROBE_FLAG_OPTIMIZED, a optimized_kprobe
may be in the optimizing or unoptimizing state when op.kp->flags
has KPROBE_FLAG_OPTIMIZED and op->list is not empty.
The __recover_optprobed_insn check logic is incorrect, a kprobe in the
unoptimizing state may be incorrectly determined as unoptimizing.
As a result, incorrect instructions are copied.
The optprobe_queued_unopt function needs to be exported for invoking in
arch directory.
Link: https://lore.kernel.org/all/20230216034247.32348-2-yangjihong1@huawei.com/
Fixes: f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code")
Cc: stable@vger.kernel.org
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a2b07fa7b93321c059af0c6d492cc9a4f1e390aa upstream.
Disable SVM and more importantly force GIF=1 when halting a CPU or
rebooting the machine. Similar to VMX, SVM allows software to block
INITs via CLGI, and thus can be problematic for a crash/reboot. The
window for failure is smaller with SVM as INIT is only blocked while
GIF=0, i.e. between CLGI and STGI, but the window does exist.
Fixes: fba4f472b33a ("x86/reboot: Turn off KVM when halting a CPU")
Cc: stable@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221130233650.1404148-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d81f952aa657b76cea381384bef1fea35c5fd266 upstream.
Disable SVM on all CPUs via NMI shootdown during an emergency reboot.
Like VMX, SVM can block INIT, e.g. if the emergency reboot is triggered
between CLGI and STGI, and thus can prevent bringing up other CPUs via
INIT-SIPI-SIPI.
Cc: stable@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221130233650.1404148-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 26044aff37a5455b19a91785086914fd33053ef4 upstream.
Disable virtualization in crash_nmi_callback() and rework the
emergency_vmx_disable_all() path to do an NMI shootdown if and only if a
shootdown has not already occurred. NMI crash shootdown fundamentally
can't support multiple invocations as responding CPUs are deliberately
put into halt state without unblocking NMIs. But, the emergency reboot
path doesn't have any work of its own, it simply cares about disabling
virtualization, i.e. so long as a shootdown occurred, emergency reboot
doesn't care who initiated the shootdown, or when.
If "crash_kexec_post_notifiers" is specified on the kernel command line,
panic() will invoke crash_smp_send_stop() and result in a second call to
nmi_shootdown_cpus() during native_machine_emergency_restart().
Invoke the callback _before_ disabling virtualization, as the current
VMCS needs to be cleared before doing VMXOFF. Note, this results in a
subtle change in ordering between disabling virtualization and stopping
Intel PT on the responding CPUs. While VMX and Intel PT do interact,
VMXOFF and writes to MSR_IA32_RTIT_CTL do not induce faults between one
another, which is all that matters when panicking.
Harden nmi_shootdown_cpus() against multiple invocations to try and
capture any such kernel bugs via a WARN instead of hanging the system
during a crash/dump, e.g. prior to the recent hardening of
register_nmi_handler(), re-registering the NMI handler would trigger a
double list_add() and hang the system if CONFIG_BUG_ON_DATA_CORRUPTION=y.
list_add double add: new=ffffffff82220800, prev=ffffffff8221cfe8, next=ffffffff82220800.
WARNING: CPU: 2 PID: 1319 at lib/list_debug.c:29 __list_add_valid+0x67/0x70
Call Trace:
__register_nmi_handler+0xcf/0x130
nmi_shootdown_cpus+0x39/0x90
native_machine_emergency_restart+0x1c9/0x1d0
panic+0x237/0x29b
Extract the disabling logic to a common helper to deduplicate code, and
to prepare for doing the shootdown in the emergency reboot path if SVM
is supported.
Note, prior to commit ed72736183c4 ("x86/reboot: Force all cpus to exit
VMX root if VMX is supported"), nmi_shootdown_cpus() was subtly protected
against a second invocation by a cpu_vmx_enabled() check as the kdump
handler would disable VMX if it ran first.
Fixes: ed72736183c4 ("x86/reboot: Force all cpus to exit VMX root if VMX is supported")
Cc: stable@vger.kernel.org
Reported-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/all/20220427224924.592546-2-gpiccoli@igalia.com
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221130233650.1404148-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6a3236580b0b1accc3976345e723104f74f6f8e6 upstream.
Set GIF=1 prior to disabling SVM to ensure that INIT is recognized if the
kernel is disabling SVM in an emergency, e.g. if the kernel is about to
jump into a crash kernel or may reboot without doing a full CPU RESET.
If GIF is left cleared, the new kernel (or firmware) will be unabled to
awaken APs. Eat faults on STGI (due to EFER.SVME=0) as it's possible
that SVM could be disabled via NMI shootdown between reading EFER.SVME
and executing STGI.
Link: https://lore.kernel.org/all/cbcb6f35-e5d7-c1c9-4db9-fe5cc4de579a@amd.com
Cc: stable@vger.kernel.org
Cc: Andrew Cooper <Andrew.Cooper3@citrix.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221130233650.1404148-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 0125acda7d76b943ca55811df40ed6ec0ecf670f ]
Currently, x86_spec_ctrl_base is read at boot time and speculative bits
are set if Kconfig items are enabled. For example, IBRS is enabled if
CONFIG_CPU_IBRS_ENTRY is configured, etc. These MSR bits are not cleared
if the mitigations are disabled.
This is a problem when kexec-ing a kernel that has the mitigation
disabled from a kernel that has the mitigation enabled. In this case,
the MSR bits are not cleared during the new kernel boot. As a result,
this might have some performance degradation that is hard to pinpoint.
This problem does not happen if the machine is (hard) rebooted because
the bit will be cleared by default.
[ bp: Massage. ]
Suggested-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20221128153148.1129350-1-leitao@debian.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 2c10b61421a28e95a46ab489fd56c0f442ff6952 upstream.
When calling the KVM_GET_DEBUGREGS ioctl, on some configurations, there
might be some unitialized portions of the kvm_debugregs structure that
could be copied to userspace. Prevent this as is done in the other kvm
ioctls, by setting the whole structure to 0 before copying anything into
it.
Bonus is that this reduces the lines of code as the explicit flag
setting and reserved space zeroing out can be removed.
Cc: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: <x86@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: stable <stable@kernel.org>
Reported-by: Xingyuan Mo <hdthky0@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Message-Id: <20230214103304.3689213-1-gregkh@linuxfoundation.org>
Tested-by: Xingyuan Mo <hdthky0@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit a00d020f18dbe0666e221d929846f1b591b27c20 which is
commit 55228db2697c09abddcb9487c3d9fa5854a932cd upstream.
_Alignof is not in the gcc version that the 4.19.y kernel still
supports (4.6), so this change needs to be reverted as it breaks the
build on those older compiler versions.
Reported-by: Michael Nies <michael.nies@netclusive.com>
Link: https://lore.kernel.org/r/HE1PR0902MB188277E37DED663AE440510BE1D99@HE1PR0902MB1882.eurprd09.prod.outlook.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217013
Cc: YingChi Long <me@inclyc.cn>
Cc: Borislav Petkov <bp@suse.de>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit a44b331614e6f7e63902ed7dff7adc8c85edd8bc ]
When serializing and deserializing kvm_sregs, attributes of the segment
descriptors are stored by user space. For unusable segments,
vmx_segment_access_rights skips all attributes and sets them to 0.
This means we zero out the DPL (Descriptor Privilege Level) for unusable
entries.
Unusable segments are - contrary to their name - usable in 64bit mode and
are used by guests to for example create a linear map through the
NULL selector.
VMENTER checks if SS.DPL is correct depending on the CS segment type.
For types 9 (Execute Only) and 11 (Execute Read), CS.DPL must be equal to
SS.DPL [1].
We have seen real world guests setting CS to a usable segment with DPL=3
and SS to an unusable segment with DPL=3. Once we go through an sregs
get/set cycle, SS.DPL turns to 0. This causes the virtual machine to crash
reproducibly.
This commit changes the attribute logic to always preserve attributes for
unusable segments. According to [2] SS.DPL is always saved on VM exits,
regardless of the unusable bit so user space applications should have saved
the information on serialization correctly.
[3] specifies that besides SS.DPL the rest of the attributes of the
descriptors are undefined after VM entry if unusable bit is set. So, there
should be no harm in setting them all to the previous state.
[1] Intel SDM Vol 3C 26.3.1.2 Checks on Guest Segment Registers
[2] Intel SDM Vol 3C 27.3.2 Saving Segment Registers and Descriptor-Table
Registers
[3] Intel SDM Vol 3C 26.3.2.2 Loading Guest Segment Registers and
Descriptor-Table Registers
Cc: Alexander Graf <graf@amazon.de>
Cc: stable@vger.kernel.org
Signed-off-by: Hendrik Borghorst <hborghor@amazon.de>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
Message-Id: <20221114164823.69555-1-hborghor@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 71d9409e20934e16f2d2ea88f0d1fb9851a7da3b ]
MSR_IA32_XSS has no relation to the VMCS whatsoever, it doesn't belong
in setup_vmcs_config() and its reference to host_xss prevents moving
setup_vmcs_config() to a dedicated file.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Stable-dep-of: a44b331614e6 ("KVM: x86/vmx: Do not skip segment attributes if unusable bit is set")
Signed-off-by: Sasha Levin <sashal@kernel.org>
