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apic::init_apic_ldr() is only invoked when the APIC is initialized. So
there is really no point in having:
- Default empty callbacks all over the place
- Two implementations of the actual LDR init function where one is
just unreadable gunk but does exactly the same as the other.
Make the apic::init_apic_ldr() invocation conditional, remove the empty
callbacks and consolidate the two implementation into one.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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It's a copy of default_cpu_present_to_apicid() with the omission of the
actual check whether the CPU is present.
This APIC callback should die completely, but the XEN APIC implementation
does something different which needs to be addressed first.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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If the system has more than 8 CPUs then XAPIC and the bigsmp APIC driver is
required. This is ensured via:
1) Enumerating all possible CPUs up to NR_CPUS
2) Checking at boot CPU APIC setup time whether the system has more than
8 CPUs and has an XAPIC.
If that's the case then it's attempted to install the bigsmp APIC
driver and a magic variable 'def_to_bigsmp' is set to one.
3) If that magic variable is set and CONFIG_X86_BIGSMP=n and the system
has more than 8 CPUs smp_sanity_check() removes all CPUs >= #8 from
the present and possible mask in the most convoluted way.
This logic is completely broken for the case where the bigsmp driver is
enabled, but not selected due to a command line option specifying the
default APIC. In that case the system boots with default APIC in logical
destination mode and fails to reduce the number of CPUs.
That aside the above which is sprinkled over 3 different places is yet
another piece of art.
It would have been too obvious to check the requirements upfront and limit
nr_cpu_ids _before_ enumerating tons of CPUs and then removing them again.
Implement exactly this. Check the bigsmp requirement when the boot APIC is
registered which happens _before_ ACPI/MPTABLE parsing and limit the number
of CPUs to 8 if it can't be used. Switch it over when the boot CPU apic is
set up if necessary.
[ dhansen: fix nr_cpu_ids off-by-one in default_setup_apic_routing() ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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On 32bit there is no APIC implementing the acpi_madt_oem_check() except XEN
PV, but that does not matter at all.
generic_apic_probe() runs before ACPI tables are parsed. This selects the
XEN APIC if there is no command line override because the XEN APIC driver
is the first to be probed.
If there is a command line override then the XEN PV driver won't be
selected in the MADT OEM check either.
As there is no other MADT check implemented for 32bit APICs, this whole
excercise is a NOOP and can be removed.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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UV X2APIC uses the per CPU variable from:
native_smp_prepare_cpus()
uv_system_init()
uv_system_init_hub()
which is long after the per CPU areas have been set up.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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Remove completely useless and mindlessly copied comments and tidy up the
code which causes eye bleed when looking at it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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This per CPU variable is just yet another form of voodoo programming. The
boot ordering is:
per_cpu(x86_cpu_to_logical_apicid, cpu) = 1U << cpu;
.....
setup_apic()
apic->init_apic_ldr()
default_init_apic_ldr()
apic_write(SET_APIC_LOGICAL_ID(1UL << smp_processor_id(), APIC_LDR);
id = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR);
WARN_ON(id != per_cpu(x86_cpu_to_logical_apicid, cpu));
per_cpu(x86_cpu_to_logical_apicid, cpu) = id;
So first write the default into LDR and then validate it against the same default
which was set up during early boot APIC enumeration.
Brilliant, isn't it?
The comment above the per CPU variable declaration describes it well:
'Let's keep it ugly for now.'
Remove the useless gunk and use '1U << cpu' consistently all over the place.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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apic::x86_32_early_logical_apicid() is yet another historical joke.
It is used to preset the x86_cpu_to_logical_apicid per CPU variable during
APIC enumeration with:
- 1 shifted left by the CPU number
- the physical APIC ID in case of bigsmp
The latter is hillarious because bigsmp uses physical destination mode
which never can use the logical APIC ID.
It gets even worse. As bigsmp can be enforced late in the boot process the
probe function overwrites the per CPU variable which is never used for this
APIC type once again.
Remove that gunk and store 1 << cpunr unconditionally if and only if the
CPU number is less than 8, because the default logical destination mode
only allows up to 8 CPUs.
This is just an intermediate step before removing the per CPU insanity
completely. Stay tuned.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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No need for an extra variable to find out whether the APIC has been mapped
or is accessible (X2APIC mode).
Provide an inline for this and check apic_mmio_base which is only set when
the local APIC has been mapped.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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The only silly usage site is gone. Remove the gunk which was even outright
wrong in the bigsmp_32 case which returned true unconditionally.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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The boot CPUs local APIC is now always registered, so there is no point to
have another unreadable validatation for it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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num_processors is 0 by default and only gets incremented when local APICs
are registered.
Make init_apic_mappings(), which tries to enable the local APIC in the case
that no SMP configuration was found set num_processors to 1.
This allows to remove yet another check for the local APIC and yet another
place which registers the boot CPUs local APIC ID.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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Convert places which just write mp_lapic_addr and let them register the
local APIC address directly instead of relying on magic other code to do
so.
Add a WARN_ON() into register_lapic_address() which is raised when
register_lapic_address() is invoked more than once during boot.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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Split the fixmap setup out of register_lapic_address() and reuse it when
the X2APIC is disabled during setup.
This avoids registering the APIC ID (setting 'mp_lapic_addr') twice.
[ dhansen: changelog wording tweak ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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Quite some APIC init functions are pure boolean, but use the success = 0,
fail < 0 model. That's confusing as hell when reading through the code.
Convert them to boolean.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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The device tree APIC parser tries to force-enable the local APIC when it is
not set in CPUID. apic_force_enable() registers the boot CPU apic on
success.
If that succeeds then dtb_lapic_setup() registers the local APIC again
eventually with a different address.
Rewrite the code so that it only registers it once.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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From: Dave Hansen <dave.hansen@linux.intel.com>
Some truly ancient code had different ways of calculating the 'apicid'
but it is long gone. Zap the unnecssary local variablee
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
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This historical leftover is really uninteresting today. Whatever MPTABLE or
MADT delivers we only trust the hardware anyway.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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Register the boot CPU APIC right when the boot CPUs APIC is read from the
hardware. No point is doing this on random places and having wild
heuristics to save the boot CPU APIC ID slot and CPU number 0 reserved.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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boot_cpu_physical_apicid is written in random places and in the last
consequence filled with the APIC ID read from the local APIC. That causes
it to have inconsistent state when the MPTABLE is broken. As a consequence
tons of moronic checks are sprinkled all over the place.
Consolidate the code and read it exactly once when either X2APIC mode is
detected early or when the APIC mapping is established.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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Put it to the other historical leftovers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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max_physical_apicid is assigned but never read.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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No point in having a wrapper around read_apic_id().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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It's a useless copy of x86_cpu_to_apicid.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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Another variable name which is confusing at best. Convert to bool.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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It reflects a state and not a command. Make it bool while at it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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It's not longer used outside the source file.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Tested-by: Juergen Gross <jgross@suse.com> # Xen PV (dom0 and unpriv. guest)
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Under certain circumstances, an integer division by 0 which faults, can
leave stale quotient data from a previous division operation on Zen1
microarchitectures.
Do a dummy division 0/1 before returning from the #DE exception handler
in order to avoid any leaks of potentially sensitive data.
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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microcode_mutex is only used by reload_store(). It has a comment saying
"to synchronize with each other". Other user of this mutex have been
removed in the commits
181b6f40e9ea8 ("x86/microcode: Rip out the OLD_INTERFACE").
b6f86689d5b74 ("x86/microcode: Rip out the subsys interface gunk")
The sysfs interface does not need additional synchronisation vs itself
because it is provided as kernfs_ops::mutex which is acquired in
kernfs_fop_write_iter().
Remove the superfluous microcode_mutex.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230804075853.JF_n6GXC@linutronix.de
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/gds fixes from Dave Hansen:
"Mitigate Gather Data Sampling issue:
- Add Base GDS mitigation
- Support GDS_NO under KVM
- Fix a documentation typo"
* tag 'gds-for-linus-2023-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Documentation/x86: Fix backwards on/off logic about YMM support
KVM: Add GDS_NO support to KVM
x86/speculation: Add Kconfig option for GDS
x86/speculation: Add force option to GDS mitigation
x86/speculation: Add Gather Data Sampling mitigation
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/srso fixes from Borislav Petkov:
"Add a mitigation for the speculative RAS (Return Address Stack)
overflow vulnerability on AMD processors.
In short, this is yet another issue where userspace poisons a
microarchitectural structure which can then be used to leak privileged
information through a side channel"
* tag 'x86_bugs_srso' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/srso: Tie SBPB bit setting to microcode patch detection
x86/srso: Add a forgotten NOENDBR annotation
x86/srso: Fix return thunks in generated code
x86/srso: Add IBPB on VMEXIT
x86/srso: Add IBPB
x86/srso: Add SRSO_NO support
x86/srso: Add IBPB_BRTYPE support
x86/srso: Add a Speculative RAS Overflow mitigation
x86/bugs: Increase the x86 bugs vector size to two u32s
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Instead of pushing/popping %RSI to/from the stack every time a function
is called from startup_64(), store it in a callee preserved register
and grab it from there when its value is actually needed.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230807162720.545787-3-ardb@kernel.org
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The SBPB bit in MSR_IA32_PRED_CMD is supported only after a microcode
patch has been applied so set X86_FEATURE_SBPB only then. Otherwise,
guests would attempt to set that bit and #GP on the MSR write.
While at it, make SMT detection more robust as some guests - depending
on how and what CPUID leafs their report - lead to cpu_smt_control
getting set to CPU_SMT_NOT_SUPPORTED but SRSO_NO should be set for any
guest incarnation where one simply cannot do SMT, for whatever reason.
Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reported-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
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The left overs of a moved interrupt are cleaned up once the interrupt is
raised on the new target CPU. Keeping the vector valid on the original
target CPU guarantees that there can't be an interrupt lost if the affinity
change races with an concurrent interrupt from the device.
This cleanup utilizes the lowest priority interrupt vector for this
cleanup, which makes sure that in the unlikely case when the to be cleaned
up interrupt is pending in the local APICs IRR the cleanup vector does not
live lock.
But there is no real reason to use an interrupt vector for cleaning up the
leftovers of a moved interrupt. It's not a high performance operation. The
only requirement is that it happens on the original target CPU.
Convert it to use a timer instead and adjust the code accordingly.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230621171248.6805-3-xin3.li@intel.com
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Rename send_cleanup_vector() to vector_schedule_cleanup() to prepare for
replacing the vector cleanup IPI with a timer callback.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Link: https://lore.kernel.org/r/20230621171248.6805-2-xin3.li@intel.com
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Now that the driver core allows for struct class to be in read-only
memory, move the pseudo_lock_class structure to be declared at build
time placing it into read-only memory, instead of having to be
dynamically allocated at boot time.
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Reinette Chatre <reinette.chatre@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: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20230620144431.583290-6-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Now that the driver core allows for struct class to be in read-only
memory, move the msr_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.
Cc: "H. Peter Anvin" <hpa@zytor.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
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20230620144431.583290-5-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Now that the driver core allows for struct class to be in read-only
memory, move the cpuid_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.
Cc: "H. Peter Anvin" <hpa@zytor.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
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20230620144431.583290-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Under W=1, this warning is visible in Clang 16 and newer:
arch/x86/kernel/paravirt.c:337:4: warning: cast from 'void (*)(struct mmu_gather *, struct page *)' to 'void (*)(struct mmu_gather *, void *)' converts to incompatible function type [-Wcast-function-type-strict]
(void (*)(struct mmu_gather *, void *))tlb_remove_page,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Add a direct wrapper instead, which will make this warning (and
potential KCFI failures) go away.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202307260332.pJntWR6o-lkp@intel.com/
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Ajay Kaher <akaher@vmware.com>
Cc: Alexey Makhalov <amakhalov@vmware.com>
Cc: VMware PV-Drivers Reviewers <pv-drivers@vmware.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: virtualization@lists.linux-foundation.org
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20230726231139.never.601-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
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Expose the crash/reboot hooks used by KVM to disable virtualization in
hardware and unblock INIT only if there's a potential in-tree user,
i.e. either KVM_INTEL or KVM_AMD is enabled.
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Attempt to disable virtualization during an emergency reboot if and only
if there is a registered virt callback, i.e. iff a hypervisor (KVM) is
active. If there's no active hypervisor, then the CPU can't be operating
with VMX or SVM enabled (barring an egregious bug).
Checking for a valid callback instead of simply for SVM or VMX support
can also eliminates spurious NMIs by avoiding the unecessary call to
nmi_shootdown_cpus_on_restart().
Note, IRQs are disabled, which prevents KVM from coming along and
enabling virtualization after the fact.
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Move the various "disable virtualization" helpers above the emergency
reboot path so that emergency_reboot_disable_virtualization() can be
stubbed out in a future patch if neither KVM_INTEL nor KVM_AMD is enabled,
i.e. if there is no in-tree user of CPU virtualization.
No functional change intended.
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-7-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Assert that IRQs are disabled when turning off virtualization in an
emergency. KVM enables hardware via on_each_cpu(), i.e. could re-enable
hardware if a pending IPI were delivered after disabling virtualization.
Remove a misleading comment from emergency_reboot_disable_virtualization()
about "just" needing to guarantee the CPU is stable (see above).
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Use the virt callback to disable SVM (and set GIF=1) during an emergency
instead of blindly attempting to disable SVM. Like the VMX case, if a
hypervisor, i.e. KVM, isn't loaded/active, SVM can't be in use.
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Use KVM VMX's reboot/crash callback to do VMXOFF in an emergency instead
of manually and blindly doing VMXOFF. There's no need to attempt VMXOFF
if a hypervisor, i.e. KVM, isn't loaded/active, i.e. if the CPU can't
possibly be post-VMXON.
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Provide dedicated helpers to (un)register virt hooks used during an
emergency crash/reboot, and WARN if there is an attempt to overwrite
the registered callback, or an attempt to do an unpaired unregister.
Opportunsitically use rcu_assign_pointer() instead of RCU_INIT_POINTER(),
mainly so that the set/unset paths are more symmetrical, but also because
any performance gains from using RCU_INIT_POINTER() are meaningless for
this code.
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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VMCLEAR active VMCSes before any emergency reboot, not just if the kernel
may kexec into a new kernel after a crash. Per Intel's SDM, the VMX
architecture doesn't require the CPU to flush the VMCS cache on INIT. If
an emergency reboot doesn't RESET CPUs, cached VMCSes could theoretically
be kept and only be written back to memory after the new kernel is booted,
i.e. could effectively corrupt memory after reboot.
Opportunistically remove the setting of the global pointer to NULL to make
checkpatch happy.
Cc: Andrew Cooper <Andrew.Cooper3@citrix.com>
Link: https://lore.kernel.org/r/20230721201859.2307736-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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The native_pv_lock_init() function is only used in SMP configurations
and declared in asm/qspinlock.h which is not used in UP kernels, but
the function is still defined for both, which causes a warning:
arch/x86/kernel/paravirt.c:76:13: error: no previous prototype for 'native_pv_lock_init' [-Werror=missing-prototypes]
Move the declaration to asm/paravirt.h so it is visible even
with CONFIG_SMP but short-circuit the definition to turn it
into an empty function.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230803082619.1369127-7-arnd@kernel.org
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The newly introduced selftest function causes a warning when -Wmissing-prototypes
is enabled:
arch/x86/kernel/alternative.c:1461:32: error: no previous prototype for '__alt_reloc_selftest' [-Werror=missing-prototypes]
Since it's only used locally, add the prototype directly in front of it.
Fixes: 270a69c4485d ("x86/alternative: Support relocations in alternatives")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230803082619.1369127-6-arnd@kernel.org
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The existing comment around handling vm_munmap() failure when freeing a
shadow stack is wrong. It asserts that vm_munmap() returns -EINTR when
the mmap lock is only being held for a short time, and so the caller
should retry. Based on this wrong understanding, unmap_shadow_stack() will
loop retrying vm_munmap().
What -EINTR actually means in this case is that the process is going
away (see ae79878), and the whole MM will be torn down soon. In order
to facilitate this, the task should not linger in the kernel, but
actually do the opposite. So don't loop in this scenario, just abandon
the operation and let exit_mmap() clean it up. Also, update the comment
to reflect the actual meaning of the error code.
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20230706233858.446232-1-rick.p.edgecombe%40intel.com
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