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By default, KVM/SVM will intercept attempts by the guest to transition
out of C0. However, the KVM_CAP_X86_DISABLE_EXITS capability can be used
by a VMM to change this behavior. To mitigate the cross-thread return
address predictions bug (X86_BUG_SMT_RSB), a VMM must not be allowed to
override the default behavior to intercept C0 transitions.
Use a module parameter to control the mitigation on processors that are
vulnerable to X86_BUG_SMT_RSB. If the processor is vulnerable to the
X86_BUG_SMT_RSB bug and the module parameter is set to mitigate the bug,
KVM will not allow the disabling of the HLT, MWAIT and CSTATE exits.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <4019348b5e07148eb4d593380a5f6713b93c9a16.1675956146.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Certain AMD processors are vulnerable to a cross-thread return address
predictions bug. When running in SMT mode and one of the sibling threads
transitions out of C0 state, the other sibling thread could use return
target predictions from the sibling thread that transitioned out of C0.
The Spectre v2 mitigations cover the Linux kernel, as it fills the RSB
when context switching to the idle thread. However, KVM allows a VMM to
prevent exiting guest mode when transitioning out of C0. A guest could
act maliciously in this situation, so create a new x86 BUG that can be
used to detect if the processor is vulnerable.
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <91cec885656ca1fcd4f0185ce403a53dd9edecb7.1675956146.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that we use the ECB/CBC macros, none of the asm functions in
blowfish-x86_64 are called indirectly. So we can safely use
SYM_FUNC_START instead of SYM_TYPED_FUNC_START with no effect, allowing
us to remove an include.
Signed-off-by: Peter Lafreniere <peter@n8pjl.ca>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
We can simplify the blowfish-x86_64 glue code by using the preexisting
ECB/CBC helper macros. Additionally, this allows for easier reuse of asm
functions in later x86 implementations of blowfish.
This involves:
1 - Modifying blowfish_dec_blk_4way() to xor outputs when a flag is
passed.
2 - Renaming blowfish_dec_blk_4way() to __blowfish_dec_blk_4way().
3 - Creating two wrapper functions around __blowfish_dec_blk_4way() for
use in the ECB/CBC macros.
4 - Removing the custom ecb_encrypt() and cbc_encrypt() routines in
favor of macro-based routines.
Signed-off-by: Peter Lafreniere <peter@n8pjl.ca>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The blowfish-x86_64 encryption functions have an unused argument. Remove
it.
This involves:
1 - Removing xor_block() macros.
2 - Removing handling of fourth argument from __blowfish_enc_blk{,_4way}()
functions.
3 - Renaming __blowfish_enc_blk{,_4way}() to blowfish_enc_blk{,_4way}().
4 - Removing the blowfish_enc_blk{,_4way}() wrappers from
blowfish_glue.c
5 - Temporarily using SYM_TYPED_FUNC_START for now indirectly-callable
encode functions.
Signed-off-by: Peter Lafreniere <peter@n8pjl.ca>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Intel confirmed the existence of this CPU in Q4'2022
earnings presentation.
Add the CPU model number.
[ dhansen: Merging these as soon as possible makes it easier
on all the folks developing model-specific features. ]
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20230208172340.158548-1-tony.luck%40intel.com
Commit 3bc753c06dd0 ("kbuild: treat char as always unsigned") broke
kprobes. Setting a probe-point on 1 byte conditional jump can cause the
kernel to crash when the (signed) relative jump offset gets treated as
unsigned.
Fix by replacing the unsigned 'immediate.bytes' (plus a cast) with the
signed 'immediate.value' when assigning to the relative jump offset.
[ dhansen: clarified changelog ]
Fixes: 3bc753c06dd0 ("kbuild: treat char as always unsigned")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20230208071708.4048-1-namit%40vmware.com
Fix those:
In file included from arch/x86/entry/vdso/vdso32/vclock_gettime.c:4:
arch/x86/entry/vdso/vdso32/../vclock_gettime.c:70:5: warning: no previous prototype for ‘__vdso_clock_gettime64’ [-Wmissing-prototypes]
70 | int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts)
|
In file included from arch/x86/entry/vdso/vdso32/vgetcpu.c:3:
arch/x86/entry/vdso/vdso32/../vgetcpu.c:13:1: warning: no previous prototype for ‘__vdso_getcpu’ [-Wmissing-prototypes]
13 | __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
| ^~~~~~~~~~~~~
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/202302070742.iYcnoJwk-lkp@intel.com
The 64bit register constrains in __arch_hweight64() cannot be
fulfilled in a 32-bit build. The function is only declared but not used
within vclock_gettime.c and gcc does not care. LLVM complains and
aborts. Reportedly because it validates extended asm even if latter
would get compiled out, see
https://lore.kernel.org/r/Y%2BJ%2BUQ1vAKr6RHuH@dev-arch.thelio-3990X
i.e., a long standing design difference between gcc and LLVM.
Move the "fake a 32 bit kernel configuration" bits from vclock_gettime.c
into a common header file. Use this from vclock_gettime.c and vgetcpu.c.
[ bp: Add background info from Nathan. ]
Fixes: 92d33063c081a ("x86/vdso: Provide getcpu for x86-32.")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/Y+IsCWQdXEr8d9Vy@linutronix.de
Unconditionally enabling TSC watchdog checking of the HPET and PMTMR
clocksources can degrade latency and performance. Therefore, provide
a new "watchdog" option to the tsc= boot parameter that opts into such
checking. Note that tsc=watchdog is overridden by a tsc=nowatchdog
regardless of their relative positions in the list of boot parameters.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Waiman Long <longman@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Wire up __vdso_getcpu() for x86-32.
The 64bit version is reused with trivial modifications. Contrary to
vclock_gettime.c there is no requirement to fake any defines in the case of
32bit VDSO on a 64bit kernel because the GDT entry from which the CPU and
node information is read is always the native one.
Adopt vdso_getcpu.c by:
- removing the unneeded time* header files which lead to compile errors
for 32bit.
- adding segment.h which provides vdso_read_cpunode() and the defines
required by it.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221125094216.3663444-3-bigeasy@linutronix.de
setup_getcpu() configures two things:
- it writes the current CPU & node information into MSR_TSC_AUX
- it writes the same information as a GDT entry.
By using the "full" setup_getcpu() on i386 it is possible to read the CPU
information in userland via RDTSCP() or via LSL from the GDT.
Provide an GDT_ENTRY_CPUNODE for x86-32 and make the setup function
unconditionally available.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Link: https://lore.kernel.org/r/20221125094216.3663444-2-bigeasy@linutronix.de
Return an error from the late loading function which is run on each CPU
only when an error has actually been encountered during the update.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230130161709.11615-5-bp@alien8.de
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
Currently the ecb/cbc macros hold fpu context unnecessarily when using
scalar cipher routines (e.g. when handling odd sizes of blocks per walk).
Change the macros to drop fpu context as soon as the fpu is out of use.
No performance impact found (on Intel Haswell).
Signed-off-by: Peter Lafreniere <peter@n8pjl.ca>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
On systems with two or fewer sockets, when the boot CPU has CONSTANT_TSC,
NONSTOP_TSC, and TSC_ADJUST, clocksource watchdog verification of the
TSC is disabled. This works well much of the time, but there is the
occasional production-level system that meets all of these criteria, but
which still has a TSC that skews significantly from atomic-clock time.
This is usually attributed to a firmware or hardware fault. Yes, the
various NTP daemons do express their opinions of userspace-to-atomic-clock
time skew, but they put them in various places, depending on the daemon
and distro in question. It would therefore be good for the kernel to
have some clue that there is a problem.
The old behavior of marking the TSC unstable is a non-starter because a
great many workloads simply cannot tolerate the overheads and latencies
of the various non-TSC clocksources. In addition, NTP-corrected systems
sometimes can tolerate significant kernel-space time skew as long as
the userspace time sources are within epsilon of atomic-clock time.
Therefore, when watchdog verification of TSC is disabled, enable it for
HPET and PMTMR (AKA ACPI PM timer). This provides the needed in-kernel
time-skew diagnostic without degrading the system's performance.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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: "H. Peter Anvin" <hpa@zytor.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Waiman Long <longman@redhat.com>
Cc: <x86@kernel.org>
Tested-by: Feng Tang <feng.tang@intel.com>
The kernel assumes that the TSC frequency which is provided by the
hardware / firmware via MSRs or CPUID(0x15) is correct after applying
a few basic consistency checks. This disables the TSC recalibration
against HPET or PM timer.
As a result there is no mechanism to validate that frequency in cases
where a firmware or hardware defect is suspected. And there was case
that some user used atomic clock to measure the TSC frequency and
reported an inaccuracy issue, which was later fixed in firmware.
Add an option 'recalibrate' for 'tsc' kernel parameter to force the
tsc freq recalibration with HPET or PM timer, and warn if the
deviation from previous value is more than about 500 PPM, which
provides a way to verify the data from hardware / firmware.
There is no functional change to existing work flow.
Recently there was a real-world case: "The 40ms/s divergence between
TSC and HPET was observed on hardware that is quite recent" [1], on
that platform the TSC frequence 1896 MHz was got from CPUID(0x15),
and the force-reclibration with HPET/PMTIMER both calibrated out
value of 1975 MHz, which also matched with check from software
'chronyd', indicating it's a problem of BIOS or firmware.
[Thanks tglx for helping improving the commit log]
[ paulmck: Wordsmith Kconfig help text. ]
[1]. https://lore.kernel.org/lkml/20221117230910.GI4001@paulmck-ThinkPad-P17-Gen-1/
Signed-off-by: Feng Tang <feng.tang@intel.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: "H. Peter Anvin" <hpa@zytor.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: <x86@kernel.org>
Cc: <linux-doc@vger.kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reading DR[0-3]_ADDR_MASK MSRs takes about 250 cycles which is going to
be noticeable with the AMD KVM SEV-ES DebugSwap feature enabled. KVM is
going to store host's DR[0-3] and DR[0-3]_ADDR_MASK before switching to
a guest; the hardware is going to swap these on VMRUN and VMEXIT.
Store MSR values passed to set_dr_addr_mask() in percpu variables
(when changed) and return them via new amd_get_dr_addr_mask().
The gain here is about 10x.
As set_dr_addr_mask() uses the array too, change the @dr type to
unsigned to avoid checking for <0. And give it the amd_ prefix to match
the new helper as the whole DR_ADDR_MASK feature is AMD-specific anyway.
While at it, replace deprecated boot_cpu_has() with cpu_feature_enabled()
in set_dr_addr_mask().
Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230120031047.628097-2-aik@amd.com
Microcode gets reloaded late only if "1" is written to the reload file.
However, the code silently treats any other unsigned integer as a
successful write even though no actions are performed to load microcode.
Make the loader more strict to accept only "1" as a trigger value and
return an error otherwise.
[ bp: Massage commit message. ]
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230130213955.6046-3-ashok.raj@intel.com
Clang likes to create conditional tail calls like:
0000000000000350 <amd_pmu_add_event>:
350: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 351: R_X86_64_NONE __fentry__-0x4
355: 48 83 bf 20 01 00 00 00 cmpq $0x0,0x120(%rdi)
35d: 0f 85 00 00 00 00 jne 363 <amd_pmu_add_event+0x13> 35f: R_X86_64_PLT32 __SCT__amd_pmu_branch_add-0x4
363: e9 00 00 00 00 jmp 368 <amd_pmu_add_event+0x18> 364: R_X86_64_PLT32 __x86_return_thunk-0x4
Where 0x35d is a static call site that's turned into a conditional
tail-call using the Jcc class of instructions.
Teach the in-line static call text patching about this.
Notably, since there is no conditional-ret, in that case patch the Jcc
to point at an empty stub function that does the ret -- or the return
thunk when needed.
Reported-by: "Erhard F." <erhard_f@mailbox.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/Y9Kdg9QjHkr9G5b5@hirez.programming.kicks-ass.net
In order to re-write Jcc.d32 instructions text_poke_bp() needs to be
taught about them.
The biggest hurdle is that the whole machinery is currently made for 5
byte instructions and extending this would grow struct text_poke_loc
which is currently a nice 16 bytes and used in an array.
However, since text_poke_loc contains a full copy of the (s32)
displacement, it is possible to map the Jcc.d32 2 byte opcodes to
Jcc.d8 1 byte opcode for the int3 emulation.
This then leaves the replacement bytes; fudge that by only storing the
last 5 bytes and adding the rule that 'length == 6' instruction will
be prefixed with a 0x0f byte.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20230123210607.115718513@infradead.org
Move the kprobe Jcc emulation into int3_emulate_jcc() so it can be
used by more code -- specifically static_call() will need this.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20230123210607.057678245@infradead.org
In order to use sched_clock() from noinstr code, mark it and all it's
implenentations noinstr.
The whole pvclock thing (used by KVM/Xen) is a bit of a pain,
since it calls out to watchdogs, create a
pvclock_clocksource_read_nowd() variant doesn't do that and can be
noinstr.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230126151323.702003578@infradead.org
Improve atomic update of last_value in pvclock_clocksource_read:
- Atomic update can be skipped if the "last_value" is already
equal to "ret".
- The detection of atomic update failure is not correct. The value,
returned by atomic64_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 "last_value" location is updated to
"ret" in an atomic way. Otherwise, the atomic update failed and
it should be retried with the value from "last_value" - exactly
what atomic64_try_cmpxchg does in a correct and more optimal way.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20230118202330.3740-1-ubizjak@gmail.com
Link: https://lore.kernel.org/r/20230126151323.643408110@infradead.org
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Merge tag 'v6.2-rc6' into sched/core, to pick up fixes
Pick up fixes before merging another batch of cpuidle updates.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In kernels compiled with CONFIG_PARAVIRT=n, the compiler re-orders the
DR7 read in exc_nmi() to happen before the call to sev_es_ist_enter().
This is problematic when running as an SEV-ES guest because in this
environment the DR7 read might cause a #VC exception, and taking #VC
exceptions is not safe in exc_nmi() before sev_es_ist_enter() has run.
The result is stack recursion if the NMI was caused on the #VC IST
stack, because a subsequent #VC exception in the NMI handler will
overwrite the stack frame of the interrupted #VC handler.
As there are no compiler barriers affecting the ordering of DR7
reads/writes, make the accesses to this register volatile, forbidding
the compiler to re-order them.
[ bp: Massage text, make them volatile too, to make sure some
aggressive compiler optimization pass doesn't discard them. ]
Fixes: 315562c9af3d ("x86/sev-es: Adjust #VC IST Stack on entering NMI handler")
Reported-by: Alexey Kardashevskiy <aik@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230127035616.508966-1-aik@amd.com
16 will support it
- Fix a NULL ptr deref when suspending with Xen PV
- Have a SEV-SNP guest check explicitly for features enabled by the hypervisor
and fail gracefully if some are unsupported by the guest instead of failing in
a non-obvious and hard-to-debug way
- Fix a MSI descriptor leakage under Xen
- Mark Xen's MSI domain as supporting MSI-X
- Prevent legacy PIC interrupts from being resent in software by marking them
level triggered, as they should be, which lead to a NULL ptr deref
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Merge tag 'x86_urgent_for_v6.2_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
- Start checking for -mindirect-branch-cs-prefix clang support too now
that LLVM 16 will support it
- Fix a NULL ptr deref when suspending with Xen PV
- Have a SEV-SNP guest check explicitly for features enabled by the
hypervisor and fail gracefully if some are unsupported by the guest
instead of failing in a non-obvious and hard-to-debug way
- Fix a MSI descriptor leakage under Xen
- Mark Xen's MSI domain as supporting MSI-X
- Prevent legacy PIC interrupts from being resent in software by
marking them level triggered, as they should be, which lead to a NULL
ptr deref
* tag 'x86_urgent_for_v6.2_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/build: Move '-mindirect-branch-cs-prefix' out of GCC-only block
acpi: Fix suspend with Xen PV
x86/sev: Add SEV-SNP guest feature negotiation support
x86/pci/xen: Fixup fallout from the PCI/MSI overhaul
x86/pci/xen: Set MSI_FLAG_PCI_MSIX support in Xen MSI domain
x86/i8259: Mark legacy PIC interrupts with IRQ_LEVEL
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
__acpi_{acquire,release}_global_lock(). x86 CMPXCHG instruction returns
success in ZF flag, so this change saves a compare after CMPXCHG
(and related MOV instruction in front of CMPXCHG).
Also, try_cmpxchg() implicitly assigns old *ptr value to "old" when CMPXCHG
fails. There is no need to re-read the value in the loop.
Note that the value from *ptr should be read using READ_ONCE() to prevent
the compiler from merging, refetching or reordering the read.
No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20230116162522.4072-1-ubizjak@gmail.com
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
set_page_memtype. x86 CMPXCHG instruction returns success in ZF flag,
so this change saves a compare after cmpxchg (and related move
instruction in front of cmpxchg).
Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails. There is no need to re-read the value in the loop.
Note that the value from *ptr should be read using READ_ONCE to prevent
the compiler from merging, refetching or reordering the read.
No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230116163446.4734-1-ubizjak@gmail.com
clang correctly complains
arch/x86/kernel/cpu/resctrl/rdtgroup.c:1456:6: warning: variable \
'h' set but not used [-Wunused-but-set-variable]
u32 h;
^
but it can't know whether this use is innocuous or really a problem.
There's a reason why those warning switches are behind a W=1 and not
enabled by default - yes, one needs to do:
make W=1 CC=clang HOSTCC=clang arch/x86/kernel/cpu/resctrl/
with clang 14 in order to trigger it.
I would normally not take a silly fix like that but this one is simple
and doesn't make the code uglier so...
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/202301242015.kbzkVteJ-lkp@intel.com
Add the AMD Automatic IBRS feature bit to those being propagated to the guest,
and enable the guest EFER bit.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-9-kim.phillips@amd.com
The AMD Zen4 core supports a new feature called Automatic IBRS.
It is a "set-and-forget" feature that means that, like Intel's Enhanced IBRS,
h/w manages its IBRS mitigation resources automatically across CPL transitions.
The feature is advertised by CPUID_Fn80000021_EAX bit 8 and is enabled by
setting MSR C000_0080 (EFER) bit 21.
Enable Automatic IBRS by default if the CPU feature is present. It typically
provides greater performance over the incumbent generic retpolines mitigation.
Reuse the SPECTRE_V2_EIBRS spectre_v2_mitigation enum. AMD Automatic IBRS and
Intel Enhanced IBRS have similar enablement. Add NO_EIBRS_PBRSB to
cpu_vuln_whitelist, since AMD Automatic IBRS isn't affected by PBRSB-eIBRS.
The kernel command line option spectre_v2=eibrs is used to select AMD Automatic
IBRS, if available.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-8-kim.phillips@amd.com
The SMM_CTL MSR not present feature was being open-coded for KVM.
Add it to its newly added CPUID leaf 0x80000021 EAX proper.
Also drop the bit description comments now the code is more
self-describing.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-7-kim.phillips@amd.com
The Null Selector Clears Base feature was being open-coded for KVM.
Add it to its newly added native CPUID leaf 0x80000021 EAX proper.
Also drop the bit description comments now it's more self-describing.
[ bp: Convert test in check_null_seg_clears_base() too. ]
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-6-kim.phillips@amd.com
The LFENCE always serializing feature bit was defined as scattered
LFENCE_RDTSC and its native leaf bit position open-coded for KVM. Add
it to its newly added CPUID leaf 0x80000021 EAX proper. With
LFENCE_RDTSC in its proper place, the kernel's set_cpu_cap() will
effectively synthesize the feature for KVM going forward.
Also, DE_CFG[1] doesn't need to be set on such CPUs anymore.
[ bp: Massage and merge diff from Sean. ]
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-5-kim.phillips@amd.com
The "Processor ignores nested data breakpoints" feature was being
open-coded for KVM. Add the feature to its newly introduced CPUID leaf
0x80000021 EAX proper.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-4-kim.phillips@amd.com
We don't set it on PF_KTHREAD threads as they never return to userspace,
and PF_IO_WORKER threads are identical in that regard. As they keep
running in the kernel until they die, skip setting the FPU flag on them.
More of a cosmetic thing that was found while debugging and
issue and pondering why the FPU flag is set on these threads.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/560c844c-f128-555b-40c6-31baff27537f@kernel.dk
Move code from __do_cpuid_func() to kvm_set_cpu_caps() in preparation for adding
the features in their native leaf.
Also drop the bit description comments as it will be more self-describing once
the individual features are added.
Whilst there, switch to using the more efficient cpu_feature_enabled() instead
of static_cpu_has().
Note, LFENCE_RDTSC and "NULL selector clears base" are currently synthetic,
Linux-defined feature flags as Linux tracking of the features predates AMD's
definition. Keep the manual propagation of the flags from their synthetic
counterparts until the kernel fully converts to AMD's definition, otherwise KVM
would stop synthesizing the flags as intended.
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-3-kim.phillips@amd.com
Add support for CPUID leaf 80000021, EAX. The majority of the features will be
used in the kernel and thus a separate leaf is appropriate.
Include KVM's reverse_cpuid entry because features are used by VM guests, too.
[ bp: Massage commit message. ]
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230124163319.2277355-2-kim.phillips@amd.com
X86_FEATURE_PGE determines whether the CPU has enabled global page
translations support. Use the faster cpu_feature_enabled() check to
shave off some more cycles when flushing all TLB entries, including the
global ones.
What this practically saves is:
mov 0x82eb308(%rip),%rax # 0xffffffff8935bec8 <boot_cpu_data+40>
test $0x20,%ah
... which test the bit. Not a lot, but TLB flushing is a timing-sensitive
path, so anything to make it even faster.
No functional changes.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230125075013.9292-1-bp@alien8.de
- Pass the correct address to mte_clear_page_tags() on initialising
a tagged page
- Plug a race against a GICv4.1 doorbell interrupt while saving
the vgic-v3 pending state.
x86:
- A command line parsing fix and a clang compilation fix for selftests
- A fix for a longstanding VMX issue, that surprisingly was only found
now to affect real world guests
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
"ARM64:
- Pass the correct address to mte_clear_page_tags() on initialising a
tagged page
- Plug a race against a GICv4.1 doorbell interrupt while saving the
vgic-v3 pending state.
x86:
- A command line parsing fix and a clang compilation fix for
selftests
- A fix for a longstanding VMX issue, that surprisingly was only
found now to affect real world guests"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: selftests: Make reclaim_period_ms input always be positive
KVM: x86/vmx: Do not skip segment attributes if unusable bit is set
selftests: kvm: move declaration at the beginning of main()
KVM: arm64: GICv4.1: Fix race with doorbell on VPE activation/deactivation
KVM: arm64: Pass the actual page address to mte_clear_page_tags()
The event configuration for mbm_local_bytes can be changed by the
user by writing to the configuration file
/sys/fs/resctrl/info/L3_MON/mbm_local_bytes_config.
The event configuration settings are domain specific and will affect all
the CPUs in the domain.
Following are the types of events supported:
==== ===========================================================
Bits Description
==== ===========================================================
6 Dirty Victims from the QOS domain to all types of memory
5 Reads to slow memory in the non-local NUMA domain
4 Reads to slow memory in the local NUMA domain
3 Non-temporal writes to non-local NUMA domain
2 Non-temporal writes to local NUMA domain
1 Reads to memory in the non-local NUMA domain
0 Reads to memory in the local NUMA domain
==== ===========================================================
For example, to change the mbm_local_bytes_config to count all the non-temporal
writes on domain 0, the bits 2 and 3 needs to be set which is 1100b (in hex
0xc).
Run the command:
$echo 0=0xc > /sys/fs/resctrl/info/L3_MON/mbm_local_bytes_config
To change the mbm_local_bytes to count only reads to local NUMA domain 1,
the bit 0 needs to be set which 1b (in hex 0x1). Run the command:
$echo 1=0x1 > /sys/fs/resctrl/info/L3_MON/mbm_local_bytes_config
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20230113152039.770054-13-babu.moger@amd.com
The event configuration for mbm_total_bytes can be changed by the user by
writing to the file /sys/fs/resctrl/info/L3_MON/mbm_total_bytes_config.
The event configuration settings are domain specific and affect all the
CPUs in the domain.
Following are the types of events supported:
==== ===========================================================
Bits Description
==== ===========================================================
6 Dirty Victims from the QOS domain to all types of memory
5 Reads to slow memory in the non-local NUMA domain
4 Reads to slow memory in the local NUMA domain
3 Non-temporal writes to non-local NUMA domain
2 Non-temporal writes to local NUMA domain
1 Reads to memory in the non-local NUMA domain
0 Reads to memory in the local NUMA domain
==== ===========================================================
For example:
To change the mbm_total_bytes to count only reads on domain 0, the bits
0, 1, 4 and 5 needs to be set, which is 110011b (in hex 0x33).
Run the command:
$echo 0=0x33 > /sys/fs/resctrl/info/L3_MON/mbm_total_bytes_config
To change the mbm_total_bytes to count all the slow memory reads on domain 1,
the bits 4 and 5 needs to be set which is 110000b (in hex 0x30).
Run the command:
$echo 1=0x30 > /sys/fs/resctrl/info/L3_MON/mbm_total_bytes_config
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20230113152039.770054-12-babu.moger@amd.com
The event configuration can be viewed by the user by reading the configuration
file /sys/fs/resctrl/info/L3_MON/mbm_local_bytes_config. The event
configuration settings are domain specific and will affect all the CPUs in the
domain.
Following are the types of events supported:
==== ===========================================================
Bits Description
==== ===========================================================
6 Dirty Victims from the QOS domain to all types of memory
5 Reads to slow memory in the non-local NUMA domain
4 Reads to slow memory in the local NUMA domain
3 Non-temporal writes to non-local NUMA domain
2 Non-temporal writes to local NUMA domain
1 Reads to memory in the non-local NUMA domain
0 Reads to memory in the local NUMA domain
==== ===========================================================
By default, the mbm_local_bytes_config is set to 0x15 to count all the local
event types.
For example:
$cat /sys/fs/resctrl/info/L3_MON/mbm_local_bytes_config
0=0x15;1=0x15;2=0x15;3=0x15
In this case, the event mbm_local_bytes is configured with 0x15 on
domains 0 to 3.
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20230113152039.770054-11-babu.moger@amd.com