12216 Commits

Author SHA1 Message Date
Gerald Schaefer
99c2913363 mm: add PTE pointer parameter to flush_tlb_fix_spurious_fault()
s390 can do more fine-grained handling of spurious TLB protection faults,
when there also is the PTE pointer available.

Therefore, pass on the PTE pointer to flush_tlb_fix_spurious_fault() as an
additional parameter.

This will add no functional change to other architectures, but those with
private flush_tlb_fix_spurious_fault() implementations need to be made
aware of the new parameter.

Link: https://lkml.kernel.org/r/20230306161548.661740-1-gerald.schaefer@linux.ibm.com
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Acked-by: Michael Ellerman <mpe@ellerman.id.au>		[powerpc]
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28 16:20:12 -07:00
Alexander Potapenko
27f644dc5a x86: kmsan: use C versions of memset16/memset32/memset64
KMSAN must see as many memory accesses as possible to prevent false
positive reports.  Fall back to versions of
memset16()/memset32()/memset64() implemented in lib/string.c instead of
those written in assembly.

Link: https://lkml.kernel.org/r/20230303141433.3422671-3-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Suggested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28 16:20:11 -07:00
Alexander Potapenko
6dc4bd4e2f x86: kmsan: don't rename memintrinsics in uninstrumented files
clang -fsanitize=kernel-memory already replaces calls to
memset/memcpy/memmove and their __builtin_ versions with
__msan_memset/__msan_memcpy/__msan_memmove in instrumented files, so
there is no need to override them.

In non-instrumented versions we are now required to leave memset() and
friends intact, so we cannot replace them with __msan_XXX() functions.

Link: https://lkml.kernel.org/r/20230303141433.3422671-1-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Suggested-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28 16:20:11 -07:00
Jithu Joseph
c68e3d4739 x86/include/asm/msr-index.h: Add IFS Array test bits
Define MSR bitfields for enumerating support for Array BIST test.

Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230322003359.213046-5-jithu.joseph@intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2023-03-27 16:10:20 +02:00
Michael Kelley
812b0597fb x86/hyperv: Change vTOM handling to use standard coco mechanisms
Hyper-V guests on AMD SEV-SNP hardware have the option of using the
"virtual Top Of Memory" (vTOM) feature specified by the SEV-SNP
architecture. With vTOM, shared vs. private memory accesses are
controlled by splitting the guest physical address space into two
halves.

vTOM is the dividing line where the uppermost bit of the physical
address space is set; e.g., with 47 bits of guest physical address
space, vTOM is 0x400000000000 (bit 46 is set).  Guest physical memory is
accessible at two parallel physical addresses -- one below vTOM and one
above vTOM.  Accesses below vTOM are private (encrypted) while accesses
above vTOM are shared (decrypted). In this sense, vTOM is like the
GPA.SHARED bit in Intel TDX.

Support for Hyper-V guests using vTOM was added to the Linux kernel in
two patch sets[1][2]. This support treats the vTOM bit as part of
the physical address. For accessing shared (decrypted) memory, these
patch sets create a second kernel virtual mapping that maps to physical
addresses above vTOM.

A better approach is to treat the vTOM bit as a protection flag, not
as part of the physical address. This new approach is like the approach
for the GPA.SHARED bit in Intel TDX. Rather than creating a second kernel
virtual mapping, the existing mapping is updated using recently added
coco mechanisms.

When memory is changed between private and shared using
set_memory_decrypted() and set_memory_encrypted(), the PTEs for the
existing kernel mapping are changed to add or remove the vTOM bit in the
guest physical address, just as with TDX. The hypercalls to change the
memory status on the host side are made using the existing callback
mechanism. Everything just works, with a minor tweak to map the IO-APIC
to use private accesses.

To accomplish the switch in approach, the following must be done:

* Update Hyper-V initialization to set the cc_mask based on vTOM
  and do other coco initialization.

* Update physical_mask so the vTOM bit is no longer treated as part
  of the physical address

* Remove CC_VENDOR_HYPERV and merge the associated vTOM functionality
  under CC_VENDOR_AMD. Update cc_mkenc() and cc_mkdec() to set/clear
  the vTOM bit as a protection flag.

* Code already exists to make hypercalls to inform Hyper-V about pages
  changing between shared and private.  Update this code to run as a
  callback from __set_memory_enc_pgtable().

* Remove the Hyper-V special case from __set_memory_enc_dec()

* Remove the Hyper-V specific call to swiotlb_update_mem_attributes()
  since mem_encrypt_init() will now do it.

* Add a Hyper-V specific implementation of the is_private_mmio()
  callback that returns true for the IO-APIC and vTPM MMIO addresses

  [1] https://lore.kernel.org/all/20211025122116.264793-1-ltykernel@gmail.com/
  [2] https://lore.kernel.org/all/20211213071407.314309-1-ltykernel@gmail.com/

  [ bp: Touchups. ]

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/1679838727-87310-7-git-send-email-mikelley@microsoft.com
2023-03-27 09:31:43 +02:00
Michael Kelley
88e378d400 x86/ioremap: Add hypervisor callback for private MMIO mapping in coco VM
Current code always maps MMIO devices as shared (decrypted) in a
confidential computing VM. But Hyper-V guest VMs on AMD SEV-SNP with vTOM
use a paravisor running in VMPL0 to emulate some devices, such as the
IO-APIC and TPM. In such a case, the device must be accessed as private
(encrypted) because the paravisor emulates the device at an address below
vTOM, where all accesses are encrypted.

Add a new hypervisor callback to determine if an MMIO address should
be mapped private. The callback allows hypervisor-specific code to handle
any quirks, the use of a paravisor, etc. in determining whether a mapping
must be private. If the callback is not used by a hypervisor, default
to returning "false", which is consistent with normal coco VM behavior.

Use this callback as another special case to check for when doing
ioremap().  Just checking the starting address is sufficient as an
ioremap range must be all private or all shared.

Also make the callback in early boot IO-APIC mapping code that uses the
fixmap.

  [ bp: Touchups. ]

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/1678329614-3482-2-git-send-email-mikelley@microsoft.com
2023-03-26 23:42:40 +02:00
Valentin Schneider
4c8c3c7f70 treewide: Trace IPIs sent via smp_send_reschedule()
To be able to trace invocations of smp_send_reschedule(), rename the
arch-specific definitions of it to arch_smp_send_reschedule() and wrap it
into an smp_send_reschedule() that contains a tracepoint.

Changes to include the declaration of the tracepoint were driven by the
following coccinelle script:

  @func_use@
  @@
  smp_send_reschedule(...);

  @include@
  @@
  #include <trace/events/ipi.h>

  @no_include depends on func_use && !include@
  @@
    #include <...>
  +
  + #include <trace/events/ipi.h>

[csky bits]
[riscv bits]
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Guo Ren <guoren@kernel.org>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230307143558.294354-6-vschneid@redhat.com
2023-03-24 11:01:28 +01:00
Mathias Krause
12aad91647 KVM: x86: Shrink struct kvm_pmu
Move the 'version' member to the beginning of the structure to reuse an
existing hole instead of introducing another one.

This allows us to save 8 bytes for 64 bit builds.

Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20230217193336.15278-2-minipli@grsecurity.net
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-23 16:10:01 -07:00
Sean Christopherson
3d8f61bf8b x86: KVM: Add common feature flag for AMD's PSFD
Use a common X86_FEATURE_* flag for AMD's PSFD, and suppress it from
/proc/cpuinfo via the standard method of an empty string instead of
hacking in a one-off "private" #define in KVM.  The request that led to
KVM defining its own flag was really just that the feature not show up
in /proc/cpuinfo, and additional patches+discussions in the interim have
clarified that defining flags in cpufeatures.h purely so that KVM can
advertise features to userspace is ok so long as the kernel already uses
a word to track the associated CPUID leaf.

No functional change intended.

Link: https://lore.kernel.org/all/d1b1e0da-29f0-c443-6c86-9549bbe1c79d@redhat.como
Link: https://lore.kernel.org/all/YxGZH7aOXQF7Pu5q@nazgul.tnic
Link: https://lore.kernel.org/all/Y3O7UYWfOLfJkwM%2F@zn.tnic
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20230124194519.2893234-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-23 16:07:29 -07:00
Josh Poimboeuf
fb799447ae x86,objtool: Split UNWIND_HINT_EMPTY in two
Mark reported that the ORC unwinder incorrectly marks an unwind as
reliable when the unwind terminates prematurely in the dark corners of
return_to_handler() due to lack of information about the next frame.

The problem is UNWIND_HINT_EMPTY is used in two different situations:

  1) The end of the kernel stack unwind before hitting user entry, boot
     code, or fork entry

  2) A blind spot in ORC coverage where the unwinder has to bail due to
     lack of information about the next frame

The ORC unwinder has no way to tell the difference between the two.
When it encounters an undefined stack state with 'end=1', it blindly
marks the stack reliable, which can break the livepatch consistency
model.

Fix it by splitting UNWIND_HINT_EMPTY into UNWIND_HINT_UNDEFINED and
UNWIND_HINT_END_OF_STACK.

Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/fd6212c8b450d3564b855e1cb48404d6277b4d9f.1677683419.git.jpoimboe@kernel.org
2023-03-23 23:18:58 +01:00
Josh Poimboeuf
4708ea14be x86,objtool: Separate unret validation from unwind hints
The ENTRY unwind hint type is serving double duty as both an empty
unwind hint and an unret validation annotation.

Unret validation is unrelated to unwinding. Separate it out into its own
annotation.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/ff7448d492ea21b86d8a90264b105fbd0d751077.1677683419.git.jpoimboe@kernel.org
2023-03-23 23:18:58 +01:00
Josh Poimboeuf
f902cfdd46 x86,objtool: Introduce ORC_TYPE_*
Unwind hints and ORC entry types are two distinct things.  Separate them
out more explicitly.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/cc879d38fff8a43f8f7beb2fd56e35a5a384d7cd.1677683419.git.jpoimboe@kernel.org
2023-03-23 23:18:57 +01:00
Josh Poimboeuf
d88ebba45d objtool: Change UNWIND_HINT() argument order
The most important argument is 'type', make that one first.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/d994f8c29376c5618c75698df28fc03b52d3a868.1677683419.git.jpoimboe@kernel.org
2023-03-23 23:18:57 +01:00
Josh Poimboeuf
1c0c1faf56 objtool: Use relative pointers for annotations
They produce the needed relocations while using half the space.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/bed05c64e28200220c9b1754a2f3ce71f73076ea.1677683419.git.jpoimboe@kernel.org
2023-03-23 23:18:56 +01:00
Santosh Shukla
fa4c027a79 KVM: x86: Add support for SVM's Virtual NMI
Add support for SVM's Virtual NMIs implementation, which adds proper
tracking of virtual NMI blocking, and an intr_ctrl flag that software can
set to mark a virtual NMI as pending.  Pending virtual NMIs are serviced
by hardware if/when virtual NMIs become unblocked, i.e. act more or less
like real NMIs.

Introduce two new kvm_x86_ops callbacks so to support SVM's vNMI, as KVM
needs to treat a pending vNMI as partially injected.  Specifically, if
two NMIs (for L1) arrive concurrently in KVM's software model, KVM's ABI
is to inject one and pend the other.  Without vNMI, KVM manually tracks
the pending NMI and uses NMI windows to detect when the NMI should be
injected.

With vNMI, the pending NMI is simply stuffed into the VMCB and handed
off to hardware.  This means that KVM needs to be able to set a vNMI
pending on-demand, and also query if a vNMI is pending, e.g. to honor the
"at most one NMI pending" rule and to preserve all NMIs across save and
restore.

Warn if KVM attempts to open an NMI window when vNMI is fully enabled,
as the above logic should prevent KVM from ever getting to
kvm_check_and_inject_events() with two NMIs pending _in software_, and
the "at most one NMI pending" logic should prevent having an NMI pending
in hardware and an NMI pending in software if NMIs are also blocked, i.e.
if KVM can't immediately inject the second NMI.

Signed-off-by: Santosh Shukla <Santosh.Shukla@amd.com>
Co-developed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20230227084016.3368-11-santosh.shukla@amd.com
[sean: rewrite shortlog and changelog, massage code comments]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-22 17:43:22 -07:00
Santosh Shukla
1c4522ab13 KVM: SVM: Add definitions for new bits in VMCB::int_ctrl related to vNMI
Add defines for three new bits in VMVC::int_ctrl that are part of SVM's
Virtual NMI (vNMI) support:

  V_NMI_PENDING_MASK(11)  - Virtual NMI is pending
  V_NMI_BLOCKING_MASK(12) - Virtual NMI is masked
  V_NMI_ENABLE_MASK(26)   - Enable NMI virtualization

To "inject" an NMI, the hypervisor (KVM) sets V_NMI_PENDING.  When the
CPU services the pending vNMI, hardware clears V_NMI_PENDING and sets
V_NMI_BLOCKING, e.g. to indicate that the vCPU is handling an NMI.
Hardware clears V_NMI_BLOCKING upon successful execution of IRET, or if a
VM-Exit occurs while delivering the virtual NMI.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Santosh Shukla <santosh.shukla@amd.com>
Link: https://lore.kernel.org/r/20230227084016.3368-10-santosh.shukla@amd.com
[sean: massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-22 17:37:44 -07:00
Chang S. Bae
a03c376eba x86/arch_prctl: Add AMX feature numbers as ABI constants
Each distinct XSAVE feature has a number assigned to it.  Among other
things, the number determines the ordering of features in the XSAVE
buffer and is also used to generate XSAVE bitmasks like the value
for XCR0.

AMX state is dynamically enabled by the architecture-specific prctl().
This prctl() takes one XSAVE feature number as an argument.  However, the
feature numbers are not defined in any readily available userspace headers.
The means that each userspace app trying to use dynamic feature prctl()s
will likely end up defining their own constants for each feature.

Since these feature numbers are a part of the uabi, expose them in the
prctl() uabi header.  Save everyone the trouble of looking them up and
defining their own.

[ dhansen: expand changelog a bit ]

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/all/20230121001900.14900-3-chang.seok.bae%40intel.com
2023-03-22 13:02:33 -07:00
Sean Christopherson
3763bf5802 x86/cpufeatures: Redefine synthetic virtual NMI bit as AMD's "real" vNMI
The existing X86_FEATURE_VNMI is a synthetic feature flag that exists
purely to maintain /proc/cpuinfo's ABI, the "real" Intel vNMI feature flag
is tracked as VMX_FEATURE_VIRTUAL_NMIS, as the feature is enumerated
through VMX MSRs, not CPUID.

AMD is also gaining virtual NMI support, but in true VMX vs. SVM form,
enumerates support through CPUID, i.e. wants to add real feature flag for
vNMI.

Redefine the syntheic X86_FEATURE_VNMI to AMD's real CPUID bit to avoid
having both X86_FEATURE_VNMI and e.g. X86_FEATURE_AMD_VNMI.

Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-22 12:34:34 -07:00
Kirill A. Shutemov
7a3a401874 x86/tdx: Drop flags from __tdx_hypercall()
After TDX_HCALL_ISSUE_STI got dropped, the only flag left is
TDX_HCALL_HAS_OUTPUT. The flag indicates if the caller wants to see
tdx_hypercall_args updated based on the hypercall output.

Drop the flags and provide __tdx_hypercall_ret() that matches
TDX_HCALL_HAS_OUTPUT semantics.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.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/20230321003511.9469-1-kirill.shutemov%40linux.intel.com
2023-03-22 11:36:05 -07:00
Andy Shevchenko
b72d6965ee x86/platform/intel-mid: Remove unused definitions from intel-mid.h
After a few rounds of removal and refactoring Intel MID related code
some artifacts are left untouched. However, they are not used anywhere.
Remove them.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20230216193958.2971-1-andriy.shevchenko%40linux.intel.com
2023-03-22 11:08:40 -07:00
Dionna Glaze
0144e3b85d x86/sev: Change snp_guest_issue_request()'s fw_err argument
The GHCB specification declares that the firmware error value for
a guest request will be stored in the lower 32 bits of EXIT_INFO_2.  The
upper 32 bits are for the VMM's own error code. The fw_err argument to
snp_guest_issue_request() is thus a misnomer, and callers will need
access to all 64 bits.

The type of unsigned long also causes problems, since sw_exit_info2 is
u64 (unsigned long long) vs the argument's unsigned long*. Change this
type for issuing the guest request. Pass the ioctl command struct's error
field directly instead of in a local variable, since an incomplete guest
request may not set the error code, and uninitialized stack memory would
be written back to user space.

The firmware might not even be called, so bookend the call with the no
firmware call error and clear the error.

Since the "fw_err" field is really exitinfo2 split into the upper bits'
vmm error code and lower bits' firmware error code, convert the 64 bit
value to a union.

  [ bp:
   - Massage commit message
   - adjust code
   - Fix a build issue as
   Reported-by: kernel test robot <lkp@intel.com>
   Link: https://lore.kernel.org/oe-kbuild-all/202303070609.vX6wp2Af-lkp@intel.com
   - print exitinfo2 in hex
   Tom:
    - Correct -EIO exit case. ]

Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230214164638.1189804-5-dionnaglaze@google.com
Link: https://lore.kernel.org/r/20230307192449.24732-12-bp@alien8.de
2023-03-21 15:43:19 +01:00
Brian Gerst
8f6be6d870 x86/smpboot: Remove initial_gs
Given its CPU#, each CPU can find its own per-cpu offset, and directly set
GSBASE accordingly. The global variable can be eliminated.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Usama Arif <usama.arif@bytedance.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Usama Arif <usama.arif@bytedance.com>
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20230316222109.1940300-9-usama.arif@bytedance.com
2023-03-21 13:35:53 +01:00
Brian Gerst
3adee777ad x86/smpboot: Remove initial_stack on 64-bit
In order to facilitate parallel startup, start to eliminate some of the
global variables passing information to CPUs in the startup path.

However, start by introducing one more: smpboot_control. For now this
merely holds the CPU# of the CPU which is coming up. Each CPU can then
find its own per-cpu data, and everything else it needs can be found
from there, allowing the other global variables to be removed.

First to be removed is initial_stack. Each CPU can load %rsp from its
current_task->thread.sp instead. That is already set up with the correct
idle thread for APs. Set up the .sp field in INIT_THREAD on x86 so that
the BSP also finds a suitable stack pointer in the static per-cpu data
when coming up on first boot.

On resume from S3, the CPU needs a temporary stack because its idle task
is already active. Instead of setting initial_stack, the sleep code can
simply set its own current->thread.sp to point to the temporary stack.
Nobody else cares about ->thread.sp for a thread which is currently on
a CPU, because the true value is actually in the %rsp register. Which
is restored with the rest of the CPU context in do_suspend_lowlevel().

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Usama Arif <usama.arif@bytedance.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Usama Arif <usama.arif@bytedance.com>
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20230316222109.1940300-7-usama.arif@bytedance.com
2023-03-21 13:35:53 +01:00
Linus Torvalds
4ac39c5910 - Check cmdline_find_option()'s return value before further processing
- Clear temporary storage in the resctrl code to prevent access to an
   unexistent MSR
 
 - Add a simple throttling mechanism to protect the hypervisor from potentially
   malicious SEV guests issuing requests in rapid succession.
 
   In order to not jeopardize the sanity of everyone involved in
   maintaining this code, the request issuing side has received
   a cleanup, split in more or less trivial, small and digestible pieces.
   Otherwise, the code was threatening to become an unmaintainable mess.
 
   Therefore, that cleanup is marked indirectly also for stable so that
   there's no differences between the upstream code and the stable
   variant when it comes down to backporting more there.
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Merge tag 'x86_urgent_for_v6.3_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:
 "There's a little bit more 'movement' in there for my taste but it
  needs to happen and should make the code better after it.

   - Check cmdline_find_option()'s return value before further
     processing

   - Clear temporary storage in the resctrl code to prevent access to an
     unexistent MSR

   - Add a simple throttling mechanism to protect the hypervisor from
     potentially malicious SEV guests issuing requests in rapid
     succession.

     In order to not jeopardize the sanity of everyone involved in
     maintaining this code, the request issuing side has received a
     cleanup, split in more or less trivial, small and digestible
     pieces. Otherwise, the code was threatening to become an
     unmaintainable mess.

     Therefore, that cleanup is marked indirectly also for stable so
     that there's no differences between the upstream code and the
     stable variant when it comes down to backporting more there"

* tag 'x86_urgent_for_v6.3_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Fix use of uninitialized buffer in sme_enable()
  x86/resctrl: Clear staged_config[] before and after it is used
  virt/coco/sev-guest: Add throttling awareness
  virt/coco/sev-guest: Convert the sw_exit_info_2 checking to a switch-case
  virt/coco/sev-guest: Do some code style cleanups
  virt/coco/sev-guest: Carve out the request issuing logic into a helper
  virt/coco/sev-guest: Remove the disable_vmpck label in handle_guest_request()
  virt/coco/sev-guest: Simplify extended guest request handling
  virt/coco/sev-guest: Check SEV_SNP attribute at probe time
2023-03-19 09:43:41 -07:00
Linus Torvalds
0eb392ec09 xen: branch for v6.3-rc3
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Merge tag 'for-linus-6.3-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes from Juergen Gross:

 - cleanup for xen time handling

 - enable the VGA console in a Xen PVH dom0

 - cleanup in the xenfs driver

* tag 'for-linus-6.3-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: remove unnecessary (void*) conversions
  x86/PVH: obtain VGA console info in Dom0
  x86/xen/time: cleanup xen_tsc_safe_clocksource
  xen: update arch/x86/include/asm/xen/cpuid.h
2023-03-17 10:45:49 -07:00
Juergen Gross
11af36cb89 x86/paravirt: Convert simple paravirt functions to asm
All functions referenced via __PV_IS_CALLEE_SAVE() need to be assembler
functions, as those functions calls are hidden from the compiler.

In case the kernel is compiled with "-fzero-call-used-regs" the compiler
will clobber caller-saved registers at the end of C functions, which
will result in unexpectedly zeroed registers at the call site of the
related paravirt functions.

Replace the C functions with DEFINE_PARAVIRT_ASM() constructs using
the same instructions as the related paravirt calls in the
PVOP_ALT_[V]CALLEE*() macros. And since they're not C functions visible
to the compiler anymore, latter won't do the callee-clobbered zeroing
invoked by -fzero-call-used-regs and thus won't corrupt registers.

  [ bp: Extend commit message. ]

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230317063325.361-1-jgross@suse.com
2023-03-17 13:29:47 +01:00
Lai Jiangshan
9fd4a4e3a3 KVM: x86/mmu: Remove FNAME(invlpg) and use FNAME(sync_spte) to update vTLB instead.
In hardware TLB, invalidating TLB entries means the translations are
removed from the TLB.

In KVM shadowed vTLB, the translations (combinations of shadow paging
and hardware TLB) are generally maintained as long as they remain "clean"
when the TLB of an address space (i.e. a PCID or all) is flushed with
the help of write-protections, sp->unsync, and kvm_sync_page(), where
"clean" in this context means that no updates to KVM's SPTEs are needed.

However, FNAME(invlpg) always zaps/removes the vTLB if the shadow page is
unsync, and thus triggers a remote flush even if the original vTLB entry
is clean, i.e. is usable as-is.

Besides this, FNAME(invlpg) is largely is a duplicate implementation of
FNAME(sync_spte) to invalidate a vTLB entry.

To address both issues, reuse FNAME(sync_spte) to share the code and
slightly modify the semantics, i.e. keep the vTLB entry if it's "clean"
and avoid remote TLB flush.

Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Link: https://lore.kernel.org/r/20230216235321.735214-3-jiangshanlai@gmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-16 17:19:54 -07:00
Lai Jiangshan
cd42853e95 kvm: x86/mmu: Use KVM_MMU_ROOT_XXX for kvm_mmu_invalidate_addr()
The @root_hpa for kvm_mmu_invalidate_addr() is called with @mmu->root.hpa
or INVALID_PAGE where @mmu->root.hpa is to invalidate gva for the current
root (the same meaning as KVM_MMU_ROOT_CURRENT) and INVALID_PAGE is to
invalidate gva for all roots (the same meaning as KVM_MMU_ROOTS_ALL).

Change the argument type of kvm_mmu_invalidate_addr() and use
KVM_MMU_ROOT_XXX instead so that we can reuse the function for
kvm_mmu_invpcid_gva() and nested_ept_invalidate_addr() for invalidating
gva for different set of roots.

No fuctionalities changed.

Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Link: https://lore.kernel.org/r/20230216154115.710033-9-jiangshanlai@gmail.com
[sean: massage comment slightly]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-16 17:19:51 -07:00
Sean Christopherson
f94db0c8b9 KVM: x86/mmu: Sanity check input to kvm_mmu_free_roots()
Tweak KVM_MMU_ROOTS_ALL to precisely cover all current+previous root
flags, and add a sanity in kvm_mmu_free_roots() to verify that the set
of roots to free doesn't stray outside KVM_MMU_ROOTS_ALL.

Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Link: https://lore.kernel.org/r/20230216154115.710033-8-jiangshanlai@gmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-16 17:19:51 -07:00
Lai Jiangshan
c3c6c9fc5d KVM: x86/mmu: Move the code out of FNAME(sync_page)'s loop body into mmu.c
Rename mmu->sync_page to mmu->sync_spte and move the code out
of FNAME(sync_page)'s loop body into mmu.c.

No functionalities change intended.

Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Link: https://lore.kernel.org/r/20230216154115.710033-6-jiangshanlai@gmail.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-16 17:19:44 -07:00
Kirill A. Shutemov
23e5d9ec2b x86/mm/iommu/sva: Make LAM and SVA mutually exclusive
IOMMU and SVA-capable devices know nothing about LAM and only expect
canonical addresses. An attempt to pass down tagged pointer will lead
to address translation failure.

By default do not allow to enable both LAM and use SVA in the same
process.

The new ARCH_FORCE_TAGGED_SVA arch_prctl() overrides the limitation.
By using the arch_prctl() userspace takes responsibility to never pass
tagged address to the device.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Reviewed-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20230312112612.31869-12-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:40 -07:00
Kirill A. Shutemov
f7d304343b mm: Expose untagging mask in /proc/$PID/status
Add a line in /proc/$PID/status to report untag_mask. It can be
used to find out LAM status of the process from the outside. It is
useful for debuggers.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-10-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:40 -07:00
Kirill A. Shutemov
2f8794bd08 x86/mm: Provide arch_prctl() interface for LAM
Add a few of arch_prctl() handles:

 - ARCH_ENABLE_TAGGED_ADDR enabled LAM. The argument is required number
   of tag bits. It is rounded up to the nearest LAM mode that can
   provide it. For now only LAM_U57 is supported, with 6 tag bits.

 - ARCH_GET_UNTAG_MASK returns untag mask. It can indicates where tag
   bits located in the address.

 - ARCH_GET_MAX_TAG_BITS returns the maximum tag bits user can request.
   Zero if LAM is not supported.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-9-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:39 -07:00
Kirill A. Shutemov
e0bddc19ba x86/mm: Reduce untagged_addr() overhead for systems without LAM
Use alternatives to reduce untagged_addr() overhead.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20230312112612.31869-8-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:39 -07:00
Kirill A. Shutemov
74c228d20a x86/uaccess: Provide untagged_addr() and remove tags before address check
untagged_addr() is a helper used by the core-mm to strip tag bits and
get the address to the canonical shape based on rules of the current
thread. It only handles userspace addresses.

The untagging mask is stored in per-CPU variable and set on context
switching to the task.

The tags must not be included into check whether it's okay to access the
userspace address. Strip tags in access_ok().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-7-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:39 -07:00
Kirill A. Shutemov
82721d8b25 x86/mm: Handle LAM on context switch
Linear Address Masking mode for userspace pointers encoded in CR3 bits.
The mode is selected per-process and stored in mm_context_t.

switch_mm_irqs_off() now respects selected LAM mode and constructs CR3
accordingly.

The active LAM mode gets recorded in the tlb_state.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-5-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:39 -07:00
Kirill A. Shutemov
6449dcb0ca x86: CPUID and CR3/CR4 flags for Linear Address Masking
Enumerate Linear Address Masking and provide defines for CR3 and CR4
flags.

The new CONFIG_ADDRESS_MASKING option enables the feature support in
kernel.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-4-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:39 -07:00
Kirill A. Shutemov
5ef495e55f x86: Allow atomic MM_CONTEXT flags setting
So far there's no need in atomic setting of MM context flags in
mm_context_t::flags. The flags set early in exec and never change
after that.

LAM enabling requires atomic flag setting. The upcoming flag
MM_CONTEXT_FORCE_TAGGED_SVA can be set much later in the process
lifetime where multiple threads exist.

Convert the field to unsigned long and do MM_CONTEXT_* accesses with
__set_bit() and test_bit().

No functional changes.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-3-kirill.shutemov%40linux.intel.com
2023-03-16 13:08:39 -07:00
Lai Jiangshan
753b43c9d1 KVM: x86/mmu: Use 64-bit address to invalidate to fix a subtle bug
FNAME(invlpg)() and kvm_mmu_invalidate_gva() take a gva_t, i.e. unsigned
long, as the type of the address to invalidate.  On 32-bit kernels, the
upper 32 bits of the GPA will get dropped when an L2 GPA address is
invalidated in the shadowed nested TDP MMU.

Convert it to u64 to fix the problem.

Reported-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Link: https://lore.kernel.org/r/20230216154115.710033-2-jiangshanlai@gmail.com
[sean: tweak changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2023-03-16 12:41:05 -07:00
Ira Weiny
b9da86e3aa x86/uaccess: Remove memcpy_page_flushcache()
Commit 21b56c847753 ("iov_iter: get rid of separate bvec and xarray
callbacks") removed the calls to memcpy_page_flushcache().

In addition, memcpy_page_flushcache() uses the deprecated
kmap_atomic().

Remove the unused x86 memcpy_page_flushcache() implementation and
also get rid of one more kmap_atomic() user.

[ dhansen: tweak changelog ]

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20221230-kmap-x86-v1-1-15f1ecccab50%40intel.com
2023-03-16 08:27:57 -07:00
Sean Christopherson
258d985f6e KVM: x86/mmu: Use EMULTYPE flag to track write #PFs to shadow pages
Use a new EMULTYPE flag, EMULTYPE_WRITE_PF_TO_SP, to track page faults
on self-changing writes to shadowed page tables instead of propagating
that information to the emulator via a semi-persistent vCPU flag.  Using
a flag in "struct kvm_vcpu_arch" is confusing, especially as implemented,
as it's not at all obvious that clearing the flag only when emulation
actually occurs is correct.

E.g. if KVM sets the flag and then retries the fault without ever getting
to the emulator, the flag will be left set for future calls into the
emulator.  But because the flag is consumed if and only if both
EMULTYPE_PF and EMULTYPE_ALLOW_RETRY_PF are set, and because
EMULTYPE_ALLOW_RETRY_PF is deliberately not set for direct MMUs, emulated
MMIO, or while L2 is active, KVM avoids false positives on a stale flag
since FNAME(page_fault) is guaranteed to be run and refresh the flag
before it's ultimately consumed by the tail end of reexecute_instruction().

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230202182817.407394-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-03-14 10:28:56 -04:00
Sean Christopherson
3ec7a1b274 KVM: SVM: Fix a benign off-by-one bug in AVIC physical table mask
Define the "physical table max index mask" as bits 8:0, not 9:0.  x2AVIC
currently supports a max of 512 entries, i.e. the max index is 511, and
the inputs to GENMASK_ULL() are inclusive.  The bug is benign as bit 9 is
reserved and never set by KVM, i.e. KVM is just clearing bits that are
guaranteed to be zero.

Note, as of this writing, APM "Rev. 3.39-October 2022" incorrectly states
that bits 11:8 are reserved in Table B-1. VMCB Layout, Control Area.  I.e.
that table wasn't updated when x2AVIC support was added.

Opportunistically fix the comment for the max AVIC ID to align with the
code, and clean up comment formatting too.

Fixes: 4d1d7942e36a ("KVM: SVM: Introduce logic to (de)activate x2AVIC mode")
Cc: stable@vger.kernel.org
Cc: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Tested-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Message-Id: <20230207002156.521736-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-03-14 10:20:06 -04:00
Dionna Glaze
72f7754dcf virt/coco/sev-guest: Add throttling awareness
A potentially malicious SEV guest can constantly hammer the hypervisor
using this driver to send down requests and thus prevent or at least
considerably hinder other guests from issuing requests to the secure
processor which is a shared platform resource.

Therefore, the host is permitted and encouraged to throttle such guest
requests.

Add the capability to handle the case when the hypervisor throttles
excessive numbers of requests issued by the guest. Otherwise, the VM
platform communication key will be disabled, preventing the guest from
attesting itself.

Realistically speaking, a well-behaved guest should not even care about
throttling. During its lifetime, it would end up issuing a handful of
requests which the hardware can easily handle.

This is more to address the case of a malicious guest. Such guest should
get throttled and if its VMPCK gets disabled, then that's its own
wrongdoing and perhaps that guest even deserves it.

To the implementation: the hypervisor signals with SNP_GUEST_REQ_ERR_BUSY
that the guest requests should be throttled. That error code is returned
in the upper 32-bit half of exitinfo2 and this is part of the GHCB spec
v2.

So the guest is given a throttling period of 1 minute in which it
retries the request every 2 seconds. This is a good default but if it
turns out to not pan out in practice, it can be tweaked later.

For safety, since the encryption algorithm in GHCBv2 is AES_GCM, control
must remain in the kernel to complete the request with the current
sequence number. Returning without finishing the request allows the
guest to make another request but with different message contents. This
is IV reuse, and breaks cryptographic protections.

  [ bp:
    - Rewrite commit message and do a simplified version.
    - The stable tags are supposed to denote that a cleanup should go
      upfront before backporting this so that any future fixes to this
      can preserve the sanity of the backporter(s). ]

Fixes: d5af44dde546 ("x86/sev: Provide support for SNP guest request NAEs")
Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
Co-developed-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@kernel.org> # d6fd48eff750 ("virt/coco/sev-guest: Check SEV_SNP attribute at probe time")
Cc: <stable@kernel.org> # 970ab823743f (" virt/coco/sev-guest: Simplify extended guest request handling")
Cc: <stable@kernel.org> # c5a338274bdb ("virt/coco/sev-guest: Remove the disable_vmpck label in handle_guest_request()")
Cc: <stable@kernel.org> # 0fdb6cc7c89c ("virt/coco/sev-guest: Carve out the request issuing logic into a helper")
Cc: <stable@kernel.org> # d25bae7dc7b0 ("virt/coco/sev-guest: Do some code style cleanups")
Cc: <stable@kernel.org> # fa4ae42cc60a ("virt/coco/sev-guest: Convert the sw_exit_info_2 checking to a switch-case")
Link: https://lore.kernel.org/r/20230214164638.1189804-2-dionnaglaze@google.com
2023-03-13 13:29:27 +01:00
Linus Torvalds
7fef099702 x86/resctl: fix scheduler confusion with 'current'
The implementation of 'current' on x86 is very intentionally special: it
is a very common thing to look up, and it uses 'this_cpu_read_stable()'
to get the current thread pointer efficiently from per-cpu storage.

And the keyword in there is 'stable': the current thread pointer never
changes as far as a single thread is concerned.  Even if when a thread
is preempted, or moved to another CPU, or even across an explicit call
'schedule()' that thread will still have the same value for 'current'.

It is, after all, the kernel base pointer to thread-local storage.
That's why it's stable to begin with, but it's also why it's important
enough that we have that special 'this_cpu_read_stable()' access for it.

So this is all done very intentionally to allow the compiler to treat
'current' as a value that never visibly changes, so that the compiler
can do CSE and combine multiple different 'current' accesses into one.

However, there is obviously one very special situation when the
currently running thread does actually change: inside the scheduler
itself.

So the scheduler code paths are special, and do not have a 'current'
thread at all.  Instead there are _two_ threads: the previous and the
next thread - typically called 'prev' and 'next' (or prev_p/next_p)
internally.

So this is all actually quite straightforward and simple, and not all
that complicated.

Except for when you then have special code that is run in scheduler
context, that code then has to be aware that 'current' isn't really a
valid thing.  Did you mean 'prev'? Did you mean 'next'?

In fact, even if then look at the code, and you use 'current' after the
new value has been assigned to the percpu variable, we have explicitly
told the compiler that 'current' is magical and always stable.  So the
compiler is quite free to use an older (or newer) value of 'current',
and the actual assignment to the percpu storage is not relevant even if
it might look that way.

Which is exactly what happened in the resctl code, that blithely used
'current' in '__resctrl_sched_in()' when it really wanted the new
process state (as implied by the name: we're scheduling 'into' that new
resctl state).  And clang would end up just using the old thread pointer
value at least in some configurations.

This could have happened with gcc too, and purely depends on random
compiler details.  Clang just seems to have been more aggressive about
moving the read of the per-cpu current_task pointer around.

The fix is trivial: just make the resctl code adhere to the scheduler
rules of using the prev/next thread pointer explicitly, instead of using
'current' in a situation where it just wasn't valid.

That same code is then also used outside of the scheduler context (when
a thread resctl state is explicitly changed), and then we will just pass
in 'current' as that pointer, of course.  There is no ambiguity in that
case.

The fix may be trivial, but noticing and figuring out what went wrong
was not.  The credit for that goes to Stephane Eranian.

Reported-by: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/lkml/20230303231133.1486085-1-eranian@google.com/
Link: https://lore.kernel.org/lkml/alpine.LFD.2.01.0908011214330.3304@localhost.localdomain/
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Tested-by: Stephane Eranian <eranian@google.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-03-08 11:48:11 -08:00
Josh Poimboeuf
eab89405b6 x86/cpu: Mark play_dead() __noreturn
play_dead() doesn't return.  Annotate it as such.  By extension this
also makes arch_cpu_idle_dead() noreturn.

Link: https://lore.kernel.org/r/f3a069e6869c51ccfdda656b76882363bc9fcfa4.1676358308.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-03-08 08:44:26 -08:00
Josh Poimboeuf
a02f50b573 x86/cpu: Make sure play_dead() doesn't return
After commit 076cbf5d2163 ("x86/xen: don't let xen_pv_play_dead()
return"), play_dead() never returns.  Make that more explicit with a
BUG().

BUG() is preferable to unreachable() because BUG() is a more explicit
failure mode and avoids undefined behavior like falling off the edge of
the function into whatever code happens to be next.

Link: https://lore.kernel.org/r/11e6ac1cf10f92967882926e3ac16287b50642f2.1676358308.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-03-08 08:44:26 -08:00
Juergen Gross
c9ae1b10d9 x86/paravirt: Merge activate_mm() and dup_mmap() callbacks
The two paravirt callbacks .mmu.activate_mm() and .mmu.dup_mmap() are
sharing the same implementations in all cases: for Xen PV guests they
are pinning the PGD of the new mm_struct, and for all other cases they
are a NOP.

In the end, both callbacks are meant to register an address space with
the underlying hypervisor, so there needs to be only a single callback
for that purpose.

So merge them to a common callback .mmu.enter_mmap() (in contrast to the
corresponding already existing .mmu.exit_mmap()).

As the first parameter of the old callbacks isn't used, drop it from the
replacement one.

  [ bp: Remove last occurrence of paravirt_activate_mm() in
    asm/mmu_context.h ]

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>
Reviewed-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Link: https://lore.kernel.org/r/20230207075902.7539-1-jgross@suse.com
2023-03-06 09:41:37 +01:00
Linus Torvalds
20fdfd55ab 17 hotfixes. Eight are for MM and seven are for other parts of the
kernel.  Seven are cc:stable and eight address post-6.3 issues or were
 judged unsuitable for -stable backporting.
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Merge tag 'mm-hotfixes-stable-2023-03-04-13-12' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "17 hotfixes.

  Eight are for MM and seven are for other parts of the kernel. Seven
  are cc:stable and eight address post-6.3 issues or were judged
  unsuitable for -stable backporting"

* tag 'mm-hotfixes-stable-2023-03-04-13-12' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mailmap: map Dikshita Agarwal's old address to his current one
  mailmap: map Vikash Garodia's old address to his current one
  fs/cramfs/inode.c: initialize file_ra_state
  fs: hfsplus: fix UAF issue in hfsplus_put_super
  panic: fix the panic_print NMI backtrace setting
  lib: parser: update documentation for match_NUMBER functions
  kasan, x86: don't rename memintrinsics in uninstrumented files
  kasan: test: fix test for new meminstrinsic instrumentation
  kasan: treat meminstrinsic as builtins in uninstrumented files
  kasan: emit different calls for instrumentable memintrinsics
  ocfs2: fix non-auto defrag path not working issue
  ocfs2: fix defrag path triggering jbd2 ASSERT
  mailmap: map Georgi Djakov's old Linaro address to his current one
  mm/hwpoison: convert TTU_IGNORE_HWPOISON to TTU_HWPOISON
  lib/zlib: DFLTCC deflate does not write all available bits for Z_NO_FLUSH
  mm/damon/paddr: fix missing folio_put()
  mm/mremap: fix dup_anon_vma() in vma_merge() case 4
2023-03-04 13:32:50 -08:00
Marco Elver
4ec4190be4 kasan, x86: don't rename memintrinsics in uninstrumented files
Now that memcpy/memset/memmove are no longer overridden by KASAN, we can
just use the normal symbol names in uninstrumented files.

Drop the preprocessor redefinitions.

Link: https://lkml.kernel.org/r/20230224085942.1791837-4-elver@google.com
Fixes: 69d4c0d32186 ("entry, kasan, x86: Disallow overriding mem*() functions")
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linux Kernel Functional Testing <lkft@linaro.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-02 21:54:22 -08:00
Linus Torvalds
857f1268a5 Changes in this cycle were:
- Shrink 'struct instruction', to improve objtool performance & memory
    footprint.
 
  - Other maximum memory usage reductions - this makes the build both faster,
    and fixes kernel build OOM failures on allyesconfig and similar configs
    when they try to build the final (large) vmlinux.o.
 
  - Fix ORC unwinding when a kprobe (INT3) is set on a stack-modifying
    single-byte instruction (PUSH/POP or LEAVE). This requires the
    extension of the ORC metadata structure with a 'signal' field.
 
  - Misc fixes & cleanups.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'objtool-core-2023-03-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:

 - Shrink 'struct instruction', to improve objtool performance & memory
   footprint

 - Other maximum memory usage reductions - this makes the build both
   faster, and fixes kernel build OOM failures on allyesconfig and
   similar configs when they try to build the final (large) vmlinux.o

 - Fix ORC unwinding when a kprobe (INT3) is set on a stack-modifying
   single-byte instruction (PUSH/POP or LEAVE). This requires the
   extension of the ORC metadata structure with a 'signal' field

 - Misc fixes & cleanups

* tag 'objtool-core-2023-03-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
  objtool: Fix ORC 'signal' propagation
  objtool: Remove instruction::list
  x86: Fix FILL_RETURN_BUFFER
  objtool: Fix overlapping alternatives
  objtool: Union instruction::{call_dest,jump_table}
  objtool: Remove instruction::reloc
  objtool: Shrink instruction::{type,visited}
  objtool: Make instruction::alts a single-linked list
  objtool: Make instruction::stack_ops a single-linked list
  objtool: Change arch_decode_instruction() signature
  x86/entry: Fix unwinding from kprobe on PUSH/POP instruction
  x86/unwind/orc: Add 'signal' field to ORC metadata
  objtool: Optimize layout of struct special_alt
  objtool: Optimize layout of struct symbol
  objtool: Allocate multiple structures with calloc()
  objtool: Make struct check_options static
  objtool: Make struct entries[] static and const
  objtool: Fix HOSTCC flag usage
  objtool: Properly support make V=1
  objtool: Install libsubcmd in build
  ...
2023-03-02 09:45:34 -08:00