<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/x86/include, branch v5.11</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'core_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2021-02-07T18:16:24+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-02-07T18:16:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c6792d44d8f08451047051351dfdcc8332a028e3'/>
<id>c6792d44d8f08451047051351dfdcc8332a028e3</id>
<content type='text'>
Pull syscall entry fixes from Borislav Petkov:

 - For syscall user dispatch, separate prctl operation from syscall
   redirection range specification before the API has been made official
   in 5.11.

 - Ensure tasks using the generic syscall code do trap after returning
   from a syscall when single-stepping is requested.

* tag 'core_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  entry: Use different define for selector variable in SUD
  entry: Ensure trap after single-step on system call return
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull syscall entry fixes from Borislav Petkov:

 - For syscall user dispatch, separate prctl operation from syscall
   redirection range specification before the API has been made official
   in 5.11.

 - Ensure tasks using the generic syscall code do trap after returning
   from a syscall when single-stepping is requested.

* tag 'core_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  entry: Use different define for selector variable in SUD
  entry: Ensure trap after single-step on system call return
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'x86_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2021-02-07T17:40:47+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-02-07T17:40:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e24f9c5f6e3127a0679d5ba5575a181b80f219c9'/>
<id>e24f9c5f6e3127a0679d5ba5575a181b80f219c9</id>
<content type='text'>
Pull x86 fixes from Borislav Petkov:
 "I hope this is the last batch of x86/urgent updates for this round:

   - Remove superfluous EFI PGD range checks which lead to those
     assertions failing with certain kernel configs and LLVM.

   - Disable setting breakpoints on facilities involved in #DB exception
     handling to avoid infinite loops.

   - Add extra serialization to non-serializing MSRs (IA32_TSC_DEADLINE
     and x2 APIC MSRs) to adhere to SDM's recommendation and avoid any
     theoretical issues.

   - Re-add the EPB MSR reading on turbostat so that it works on older
     kernels which don't have the corresponding EPB sysfs file.

   - Add Alder Lake to the list of CPUs which support split lock.

   - Fix %dr6 register handling in order to be able to set watchpoints
     with gdb again.

   - Disable CET instrumentation in the kernel so that gcc doesn't add
     ENDBR64 to kernel code and thus confuse tracing"

* tag 'x86_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Remove EFI PGD build time checks
  x86/debug: Prevent data breakpoints on cpu_dr7
  x86/debug: Prevent data breakpoints on __per_cpu_offset
  x86/apic: Add extra serialization for non-serializing MSRs
  tools/power/turbostat: Fallback to an MSR read for EPB
  x86/split_lock: Enable the split lock feature on another Alder Lake CPU
  x86/debug: Fix DR6 handling
  x86/build: Disable CET instrumentation in the kernel
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull x86 fixes from Borislav Petkov:
 "I hope this is the last batch of x86/urgent updates for this round:

   - Remove superfluous EFI PGD range checks which lead to those
     assertions failing with certain kernel configs and LLVM.

   - Disable setting breakpoints on facilities involved in #DB exception
     handling to avoid infinite loops.

   - Add extra serialization to non-serializing MSRs (IA32_TSC_DEADLINE
     and x2 APIC MSRs) to adhere to SDM's recommendation and avoid any
     theoretical issues.

   - Re-add the EPB MSR reading on turbostat so that it works on older
     kernels which don't have the corresponding EPB sysfs file.

   - Add Alder Lake to the list of CPUs which support split lock.

   - Fix %dr6 register handling in order to be able to set watchpoints
     with gdb again.

   - Disable CET instrumentation in the kernel so that gcc doesn't add
     ENDBR64 to kernel code and thus confuse tracing"

* tag 'x86_urgent_for_v5.11_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/efi: Remove EFI PGD build time checks
  x86/debug: Prevent data breakpoints on cpu_dr7
  x86/debug: Prevent data breakpoints on __per_cpu_offset
  x86/apic: Add extra serialization for non-serializing MSRs
  tools/power/turbostat: Fallback to an MSR read for EPB
  x86/split_lock: Enable the split lock feature on another Alder Lake CPU
  x86/debug: Fix DR6 handling
  x86/build: Disable CET instrumentation in the kernel
</pre>
</div>
</content>
</entry>
<entry>
<title>entry: Ensure trap after single-step on system call return</title>
<updated>2021-02-05T23:21:42+00:00</updated>
<author>
<name>Gabriel Krisman Bertazi</name>
<email>krisman@collabora.com</email>
</author>
<published>2021-02-03T18:00:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6342adcaa683c2b705c24ed201dc11b35854c88d'/>
<id>6342adcaa683c2b705c24ed201dc11b35854c88d</id>
<content type='text'>
Commit 299155244770 ("entry: Drop usage of TIF flags in the generic syscall
code") introduced a bug on architectures using the generic syscall entry
code, in which processes stopped by PTRACE_SYSCALL do not trap on syscall
return after receiving a TIF_SINGLESTEP.

The reason is that the meaning of TIF_SINGLESTEP flag is overloaded to
cause the trap after a system call is executed, but since the above commit,
the syscall call handler only checks for the SYSCALL_WORK flags on the exit
work.

Split the meaning of TIF_SINGLESTEP such that it only means single-step
mode, and create a new type of SYSCALL_WORK to request a trap immediately
after a syscall in single-step mode.  In the current implementation, the
SYSCALL_WORK flag shadows the TIF_SINGLESTEP flag for simplicity.

Update x86 to flip this bit when a tracer enables single stepping.

Fixes: 299155244770 ("entry: Drop usage of TIF flags in the generic syscall code")
Suggested-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Gabriel Krisman Bertazi &lt;krisman@collabora.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Tested-by: Kyle Huey &lt;me@kylehuey.com&gt;
Link: https://lore.kernel.org/r/87h7mtc9pr.fsf_-_@collabora.com

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 299155244770 ("entry: Drop usage of TIF flags in the generic syscall
code") introduced a bug on architectures using the generic syscall entry
code, in which processes stopped by PTRACE_SYSCALL do not trap on syscall
return after receiving a TIF_SINGLESTEP.

The reason is that the meaning of TIF_SINGLESTEP flag is overloaded to
cause the trap after a system call is executed, but since the above commit,
the syscall call handler only checks for the SYSCALL_WORK flags on the exit
work.

Split the meaning of TIF_SINGLESTEP such that it only means single-step
mode, and create a new type of SYSCALL_WORK to request a trap immediately
after a syscall in single-step mode.  In the current implementation, the
SYSCALL_WORK flag shadows the TIF_SINGLESTEP flag for simplicity.

Update x86 to flip this bit when a tracer enables single stepping.

Fixes: 299155244770 ("entry: Drop usage of TIF flags in the generic syscall code")
Suggested-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Gabriel Krisman Bertazi &lt;krisman@collabora.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Tested-by: Kyle Huey &lt;me@kylehuey.com&gt;
Link: https://lore.kernel.org/r/87h7mtc9pr.fsf_-_@collabora.com

</pre>
</div>
</content>
</entry>
<entry>
<title>x86/apic: Add extra serialization for non-serializing MSRs</title>
<updated>2021-02-04T18:36:31+00:00</updated>
<author>
<name>Dave Hansen</name>
<email>dave.hansen@linux.intel.com</email>
</author>
<published>2020-03-05T17:47:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=25a068b8e9a4eb193d755d58efcb3c98928636e0'/>
<id>25a068b8e9a4eb193d755d58efcb3c98928636e0</id>
<content type='text'>
Jan Kiszka reported that the x2apic_wrmsr_fence() function uses a plain
MFENCE while the Intel SDM (10.12.3 MSR Access in x2APIC Mode) calls for
MFENCE; LFENCE.

Short summary: we have special MSRs that have weaker ordering than all
the rest. Add fencing consistent with current SDM recommendations.

This is not known to cause any issues in practice, only in theory.

Longer story below:

The reason the kernel uses a different semantic is that the SDM changed
(roughly in late 2017). The SDM changed because folks at Intel were
auditing all of the recommended fences in the SDM and realized that the
x2apic fences were insufficient.

Why was the pain MFENCE judged insufficient?

WRMSR itself is normally a serializing instruction. No fences are needed
because the instruction itself serializes everything.

But, there are explicit exceptions for this serializing behavior written
into the WRMSR instruction documentation for two classes of MSRs:
IA32_TSC_DEADLINE and the X2APIC MSRs.

Back to x2apic: WRMSR is *not* serializing in this specific case.
But why is MFENCE insufficient? MFENCE makes writes visible, but
only affects load/store instructions. WRMSR is unfortunately not a
load/store instruction and is unaffected by MFENCE. This means that a
non-serializing WRMSR could be reordered by the CPU to execute before
the writes made visible by the MFENCE have even occurred in the first
place.

This means that an x2apic IPI could theoretically be triggered before
there is any (visible) data to process.

Does this affect anything in practice? I honestly don't know. It seems
quite possible that by the time an interrupt gets to consume the (not
yet) MFENCE'd data, it has become visible, mostly by accident.

To be safe, add the SDM-recommended fences for all x2apic WRMSRs.

This also leaves open the question of the _other_ weakly-ordered WRMSR:
MSR_IA32_TSC_DEADLINE. While it has the same ordering architecture as
the x2APIC MSRs, it seems substantially less likely to be a problem in
practice. While writes to the in-memory Local Vector Table (LVT) might
theoretically be reordered with respect to a weakly-ordered WRMSR like
TSC_DEADLINE, the SDM has this to say:

  In x2APIC mode, the WRMSR instruction is used to write to the LVT
  entry. The processor ensures the ordering of this write and any
  subsequent WRMSR to the deadline; no fencing is required.

But, that might still leave xAPIC exposed. The safest thing to do for
now is to add the extra, recommended LFENCE.

 [ bp: Massage commit message, fix typos, drop accidentally added
   newline to tools/arch/x86/include/asm/barrier.h. ]

Reported-by: Jan Kiszka &lt;jan.kiszka@siemens.com&gt;
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lkml.kernel.org/r/20200305174708.F77040DD@viggo.jf.intel.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Jan Kiszka reported that the x2apic_wrmsr_fence() function uses a plain
MFENCE while the Intel SDM (10.12.3 MSR Access in x2APIC Mode) calls for
MFENCE; LFENCE.

Short summary: we have special MSRs that have weaker ordering than all
the rest. Add fencing consistent with current SDM recommendations.

This is not known to cause any issues in practice, only in theory.

Longer story below:

The reason the kernel uses a different semantic is that the SDM changed
(roughly in late 2017). The SDM changed because folks at Intel were
auditing all of the recommended fences in the SDM and realized that the
x2apic fences were insufficient.

Why was the pain MFENCE judged insufficient?

WRMSR itself is normally a serializing instruction. No fences are needed
because the instruction itself serializes everything.

But, there are explicit exceptions for this serializing behavior written
into the WRMSR instruction documentation for two classes of MSRs:
IA32_TSC_DEADLINE and the X2APIC MSRs.

Back to x2apic: WRMSR is *not* serializing in this specific case.
But why is MFENCE insufficient? MFENCE makes writes visible, but
only affects load/store instructions. WRMSR is unfortunately not a
load/store instruction and is unaffected by MFENCE. This means that a
non-serializing WRMSR could be reordered by the CPU to execute before
the writes made visible by the MFENCE have even occurred in the first
place.

This means that an x2apic IPI could theoretically be triggered before
there is any (visible) data to process.

Does this affect anything in practice? I honestly don't know. It seems
quite possible that by the time an interrupt gets to consume the (not
yet) MFENCE'd data, it has become visible, mostly by accident.

To be safe, add the SDM-recommended fences for all x2apic WRMSRs.

This also leaves open the question of the _other_ weakly-ordered WRMSR:
MSR_IA32_TSC_DEADLINE. While it has the same ordering architecture as
the x2APIC MSRs, it seems substantially less likely to be a problem in
practice. While writes to the in-memory Local Vector Table (LVT) might
theoretically be reordered with respect to a weakly-ordered WRMSR like
TSC_DEADLINE, the SDM has this to say:

  In x2APIC mode, the WRMSR instruction is used to write to the LVT
  entry. The processor ensures the ordering of this write and any
  subsequent WRMSR to the deadline; no fencing is required.

But, that might still leave xAPIC exposed. The safest thing to do for
now is to add the extra, recommended LFENCE.

 [ bp: Massage commit message, fix typos, drop accidentally added
   newline to tools/arch/x86/include/asm/barrier.h. ]

Reported-by: Jan Kiszka &lt;jan.kiszka@siemens.com&gt;
Signed-off-by: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Link: https://lkml.kernel.org/r/20200305174708.F77040DD@viggo.jf.intel.com
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'for-linus-5.11-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip</title>
<updated>2021-01-28T18:08:08+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-01-28T18:08:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e5ff2cb9cf67a542f2ec7fb87e24934c88b32678'/>
<id>e5ff2cb9cf67a542f2ec7fb87e24934c88b32678</id>
<content type='text'>
Pull xen fixes from Juergen Gross:

 - A fix for a regression introduced in 5.11 resulting in Xen dom0
   having problems to correctly initialize Xenstore.

 - A fix for avoiding WARN splats when booting as Xen dom0 with
   CONFIG_AMD_MEM_ENCRYPT enabled due to a missing trap handler for the
   #VC exception (even if the handler should never be called).

 - A fix for the Xen bklfront driver adapting to the correct but
   unexpected behavior of new qemu.

* tag 'for-linus-5.11-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  x86/xen: avoid warning in Xen pv guest with CONFIG_AMD_MEM_ENCRYPT enabled
  xen: Fix XenStore initialisation for XS_LOCAL
  xen-blkfront: allow discard-* nodes to be optional
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull xen fixes from Juergen Gross:

 - A fix for a regression introduced in 5.11 resulting in Xen dom0
   having problems to correctly initialize Xenstore.

 - A fix for avoiding WARN splats when booting as Xen dom0 with
   CONFIG_AMD_MEM_ENCRYPT enabled due to a missing trap handler for the
   #VC exception (even if the handler should never be called).

 - A fix for the Xen bklfront driver adapting to the correct but
   unexpected behavior of new qemu.

* tag 'for-linus-5.11-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  x86/xen: avoid warning in Xen pv guest with CONFIG_AMD_MEM_ENCRYPT enabled
  xen: Fix XenStore initialisation for XS_LOCAL
  xen-blkfront: allow discard-* nodes to be optional
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/xen: avoid warning in Xen pv guest with CONFIG_AMD_MEM_ENCRYPT enabled</title>
<updated>2021-01-27T14:45:29+00:00</updated>
<author>
<name>Juergen Gross</name>
<email>jgross@suse.com</email>
</author>
<published>2021-01-25T13:42:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2e92493637a09547734f92c62a2471f6f0cb9a2c'/>
<id>2e92493637a09547734f92c62a2471f6f0cb9a2c</id>
<content type='text'>
When booting a kernel which has been built with CONFIG_AMD_MEM_ENCRYPT
enabled as a Xen pv guest a warning is issued for each processor:

[    5.964347] ------------[ cut here ]------------
[    5.968314] WARNING: CPU: 0 PID: 1 at /home/gross/linux/head/arch/x86/xen/enlighten_pv.c:660 get_trap_addr+0x59/0x90
[    5.972321] Modules linked in:
[    5.976313] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W         5.11.0-rc5-default #75
[    5.980313] Hardware name: Dell Inc. OptiPlex 9020/0PC5F7, BIOS A05 12/05/2013
[    5.984313] RIP: e030:get_trap_addr+0x59/0x90
[    5.988313] Code: 42 10 83 f0 01 85 f6 74 04 84 c0 75 1d b8 01 00 00 00 c3 48 3d 00 80 83 82 72 08 48 3d 20 81 83 82 72 0c b8 01 00 00 00 eb db &lt;0f&gt; 0b 31 c0 c3 48 2d 00 80 83 82 48 ba 72 1c c7 71 1c c7 71 1c 48
[    5.992313] RSP: e02b:ffffc90040033d38 EFLAGS: 00010202
[    5.996313] RAX: 0000000000000001 RBX: ffffffff82a141d0 RCX: ffffffff8222ec38
[    6.000312] RDX: ffffffff8222ec38 RSI: 0000000000000005 RDI: ffffc90040033d40
[    6.004313] RBP: ffff8881003984a0 R08: 0000000000000007 R09: ffff888100398000
[    6.008312] R10: 0000000000000007 R11: ffffc90040246000 R12: ffff8884082182a8
[    6.012313] R13: 0000000000000100 R14: 000000000000001d R15: ffff8881003982d0
[    6.016316] FS:  0000000000000000(0000) GS:ffff888408200000(0000) knlGS:0000000000000000
[    6.020313] CS:  e030 DS: 0000 ES: 0000 CR0: 0000000080050033
[    6.024313] CR2: ffffc900020ef000 CR3: 000000000220a000 CR4: 0000000000050660
[    6.028314] Call Trace:
[    6.032313]  cvt_gate_to_trap.part.7+0x3f/0x90
[    6.036313]  ? asm_exc_double_fault+0x30/0x30
[    6.040313]  xen_convert_trap_info+0x87/0xd0
[    6.044313]  xen_pv_cpu_up+0x17a/0x450
[    6.048313]  bringup_cpu+0x2b/0xc0
[    6.052313]  ? cpus_read_trylock+0x50/0x50
[    6.056313]  cpuhp_invoke_callback+0x80/0x4c0
[    6.060313]  _cpu_up+0xa7/0x140
[    6.064313]  cpu_up+0x98/0xd0
[    6.068313]  bringup_nonboot_cpus+0x4f/0x60
[    6.072313]  smp_init+0x26/0x79
[    6.076313]  kernel_init_freeable+0x103/0x258
[    6.080313]  ? rest_init+0xd0/0xd0
[    6.084313]  kernel_init+0xa/0x110
[    6.088313]  ret_from_fork+0x1f/0x30
[    6.092313] ---[ end trace be9ecf17dceeb4f3 ]---

Reason is that there is no Xen pv trap entry for X86_TRAP_VC.

Fix that by adding a generic trap handler for unknown traps and wire all
unknown bare metal handlers to this generic handler, which will just
crash the system in case such a trap will ever happen.

Fixes: 0786138c78e793 ("x86/sev-es: Add a Runtime #VC Exception Handler")
Cc: &lt;stable@vger.kernel.org&gt; # v5.10
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Reviewed-by: Andrew Cooper &lt;andrew.cooper3@citrix.com&gt;
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When booting a kernel which has been built with CONFIG_AMD_MEM_ENCRYPT
enabled as a Xen pv guest a warning is issued for each processor:

[    5.964347] ------------[ cut here ]------------
[    5.968314] WARNING: CPU: 0 PID: 1 at /home/gross/linux/head/arch/x86/xen/enlighten_pv.c:660 get_trap_addr+0x59/0x90
[    5.972321] Modules linked in:
[    5.976313] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W         5.11.0-rc5-default #75
[    5.980313] Hardware name: Dell Inc. OptiPlex 9020/0PC5F7, BIOS A05 12/05/2013
[    5.984313] RIP: e030:get_trap_addr+0x59/0x90
[    5.988313] Code: 42 10 83 f0 01 85 f6 74 04 84 c0 75 1d b8 01 00 00 00 c3 48 3d 00 80 83 82 72 08 48 3d 20 81 83 82 72 0c b8 01 00 00 00 eb db &lt;0f&gt; 0b 31 c0 c3 48 2d 00 80 83 82 48 ba 72 1c c7 71 1c c7 71 1c 48
[    5.992313] RSP: e02b:ffffc90040033d38 EFLAGS: 00010202
[    5.996313] RAX: 0000000000000001 RBX: ffffffff82a141d0 RCX: ffffffff8222ec38
[    6.000312] RDX: ffffffff8222ec38 RSI: 0000000000000005 RDI: ffffc90040033d40
[    6.004313] RBP: ffff8881003984a0 R08: 0000000000000007 R09: ffff888100398000
[    6.008312] R10: 0000000000000007 R11: ffffc90040246000 R12: ffff8884082182a8
[    6.012313] R13: 0000000000000100 R14: 000000000000001d R15: ffff8881003982d0
[    6.016316] FS:  0000000000000000(0000) GS:ffff888408200000(0000) knlGS:0000000000000000
[    6.020313] CS:  e030 DS: 0000 ES: 0000 CR0: 0000000080050033
[    6.024313] CR2: ffffc900020ef000 CR3: 000000000220a000 CR4: 0000000000050660
[    6.028314] Call Trace:
[    6.032313]  cvt_gate_to_trap.part.7+0x3f/0x90
[    6.036313]  ? asm_exc_double_fault+0x30/0x30
[    6.040313]  xen_convert_trap_info+0x87/0xd0
[    6.044313]  xen_pv_cpu_up+0x17a/0x450
[    6.048313]  bringup_cpu+0x2b/0xc0
[    6.052313]  ? cpus_read_trylock+0x50/0x50
[    6.056313]  cpuhp_invoke_callback+0x80/0x4c0
[    6.060313]  _cpu_up+0xa7/0x140
[    6.064313]  cpu_up+0x98/0xd0
[    6.068313]  bringup_nonboot_cpus+0x4f/0x60
[    6.072313]  smp_init+0x26/0x79
[    6.076313]  kernel_init_freeable+0x103/0x258
[    6.080313]  ? rest_init+0xd0/0xd0
[    6.084313]  kernel_init+0xa/0x110
[    6.088313]  ret_from_fork+0x1f/0x30
[    6.092313] ---[ end trace be9ecf17dceeb4f3 ]---

Reason is that there is no Xen pv trap entry for X86_TRAP_VC.

Fix that by adding a generic trap handler for unknown traps and wire all
unknown bare metal handlers to this generic handler, which will just
crash the system in case such a trap will ever happen.

Fixes: 0786138c78e793 ("x86/sev-es: Add a Runtime #VC Exception Handler")
Cc: &lt;stable@vger.kernel.org&gt; # v5.10
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
Reviewed-by: Andrew Cooper &lt;andrew.cooper3@citrix.com&gt;
Signed-off-by: Juergen Gross &lt;jgross@suse.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'x86_urgent_for_v5.11_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2021-01-24T17:46:05+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-01-24T17:46:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=17b6c49da37f5d57d76bf352d32b0ac498e7c133'/>
<id>17b6c49da37f5d57d76bf352d32b0ac498e7c133</id>
<content type='text'>
Pull x86 fixes from Borislav Petkov:

 - Add a new Intel model number for Alder Lake

 - Differentiate which aspects of the FPU state get saved/restored when
   the FPU is used in-kernel and fix a boot crash on K7 due to early
   MXCSR access before CR4.OSFXSR is even set.

 - A couple of noinstr annotation fixes

 - Correct die ID setting on AMD for users of topology information which
   need the correct die ID

 - A SEV-ES fix to handle string port IO to/from kernel memory properly

* tag 'x86_urgent_for_v5.11_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Add another Alder Lake CPU to the Intel family
  x86/mmx: Use KFPU_387 for MMX string operations
  x86/fpu: Add kernel_fpu_begin_mask() to selectively initialize state
  x86/topology: Make __max_die_per_package available unconditionally
  x86: __always_inline __{rd,wr}msr()
  x86/mce: Remove explicit/superfluous tracing
  locking/lockdep: Avoid noinstr warning for DEBUG_LOCKDEP
  locking/lockdep: Cure noinstr fail
  x86/sev: Fix nonistr violation
  x86/entry: Fix noinstr fail
  x86/cpu/amd: Set __max_die_per_package on AMD
  x86/sev-es: Handle string port IO to kernel memory properly
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull x86 fixes from Borislav Petkov:

 - Add a new Intel model number for Alder Lake

 - Differentiate which aspects of the FPU state get saved/restored when
   the FPU is used in-kernel and fix a boot crash on K7 due to early
   MXCSR access before CR4.OSFXSR is even set.

 - A couple of noinstr annotation fixes

 - Correct die ID setting on AMD for users of topology information which
   need the correct die ID

 - A SEV-ES fix to handle string port IO to/from kernel memory properly

* tag 'x86_urgent_for_v5.11_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Add another Alder Lake CPU to the Intel family
  x86/mmx: Use KFPU_387 for MMX string operations
  x86/fpu: Add kernel_fpu_begin_mask() to selectively initialize state
  x86/topology: Make __max_die_per_package available unconditionally
  x86: __always_inline __{rd,wr}msr()
  x86/mce: Remove explicit/superfluous tracing
  locking/lockdep: Avoid noinstr warning for DEBUG_LOCKDEP
  locking/lockdep: Cure noinstr fail
  x86/sev: Fix nonistr violation
  x86/entry: Fix noinstr fail
  x86/cpu/amd: Set __max_die_per_package on AMD
  x86/sev-es: Handle string port IO to kernel memory properly
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/cpu: Add another Alder Lake CPU to the Intel family</title>
<updated>2021-01-21T22:01:51+00:00</updated>
<author>
<name>Gayatri Kammela</name>
<email>gayatri.kammela@intel.com</email>
</author>
<published>2021-01-21T21:50:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6e1239c13953f3c2a76e70031f74ddca9ae57cd3'/>
<id>6e1239c13953f3c2a76e70031f74ddca9ae57cd3</id>
<content type='text'>
Add Alder Lake mobile CPU model number to Intel family.

Signed-off-by: Gayatri Kammela &lt;gayatri.kammela@intel.com&gt;
Signed-off-by: Tony Luck &lt;tony.luck@intel.com&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Link: https://lkml.kernel.org/r/20210121215004.11618-1-tony.luck@intel.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add Alder Lake mobile CPU model number to Intel family.

Signed-off-by: Gayatri Kammela &lt;gayatri.kammela@intel.com&gt;
Signed-off-by: Tony Luck &lt;tony.luck@intel.com&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Link: https://lkml.kernel.org/r/20210121215004.11618-1-tony.luck@intel.com
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/fpu: Add kernel_fpu_begin_mask() to selectively initialize state</title>
<updated>2021-01-21T11:07:28+00:00</updated>
<author>
<name>Andy Lutomirski</name>
<email>luto@kernel.org</email>
</author>
<published>2021-01-21T05:09:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e45122893a9870813f9bd7b4add4f613e6f29008'/>
<id>e45122893a9870813f9bd7b4add4f613e6f29008</id>
<content type='text'>
Currently, requesting kernel FPU access doesn't distinguish which parts of
the extended ("FPU") state are needed.  This is nice for simplicity, but
there are a few cases in which it's suboptimal:

 - The vast majority of in-kernel FPU users want XMM/YMM/ZMM state but do
   not use legacy 387 state.  These users want MXCSR initialized but don't
   care about the FPU control word.  Skipping FNINIT would save time.
   (Empirically, FNINIT is several times slower than LDMXCSR.)

 - Code that wants MMX doesn't want or need MXCSR initialized.
   _mmx_memcpy(), for example, can run before CR4.OSFXSR gets set, and
   initializing MXCSR will fail because LDMXCSR generates an #UD when the
   aforementioned CR4 bit is not set.

 - Any future in-kernel users of XFD (eXtended Feature Disable)-capable
   dynamic states will need special handling.

Add a more specific API that allows callers to specify exactly what they
want.

Signed-off-by: Andy Lutomirski &lt;luto@kernel.org&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Tested-by: Krzysztof Piotr Olędzki &lt;ole@ans.pl&gt;
Link: https://lkml.kernel.org/r/aff1cac8b8fc7ee900cf73e8f2369966621b053f.1611205691.git.luto@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently, requesting kernel FPU access doesn't distinguish which parts of
the extended ("FPU") state are needed.  This is nice for simplicity, but
there are a few cases in which it's suboptimal:

 - The vast majority of in-kernel FPU users want XMM/YMM/ZMM state but do
   not use legacy 387 state.  These users want MXCSR initialized but don't
   care about the FPU control word.  Skipping FNINIT would save time.
   (Empirically, FNINIT is several times slower than LDMXCSR.)

 - Code that wants MMX doesn't want or need MXCSR initialized.
   _mmx_memcpy(), for example, can run before CR4.OSFXSR gets set, and
   initializing MXCSR will fail because LDMXCSR generates an #UD when the
   aforementioned CR4 bit is not set.

 - Any future in-kernel users of XFD (eXtended Feature Disable)-capable
   dynamic states will need special handling.

Add a more specific API that allows callers to specify exactly what they
want.

Signed-off-by: Andy Lutomirski &lt;luto@kernel.org&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Tested-by: Krzysztof Piotr Olędzki &lt;ole@ans.pl&gt;
Link: https://lkml.kernel.org/r/aff1cac8b8fc7ee900cf73e8f2369966621b053f.1611205691.git.luto@kernel.org
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/topology: Make __max_die_per_package available unconditionally</title>
<updated>2021-01-14T11:18:36+00:00</updated>
<author>
<name>Borislav Petkov</name>
<email>bp@suse.de</email>
</author>
<published>2021-01-14T09:36:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1eb8f690bcb565a6600f8b6dcc78f7b239ceba17'/>
<id>1eb8f690bcb565a6600f8b6dcc78f7b239ceba17</id>
<content type='text'>
Move it outside of CONFIG_SMP in order to avoid ifdeffery at the usage
sites.

Fixes: 76e2fc63ca40 ("x86/cpu/amd: Set __max_die_per_package on AMD")
Reported-by: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Link: https://lkml.kernel.org/r/20210114111814.5346-1-bp@alien8.de
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Move it outside of CONFIG_SMP in order to avoid ifdeffery at the usage
sites.

Fixes: 76e2fc63ca40 ("x86/cpu/amd: Set __max_die_per_package on AMD")
Reported-by: Stephen Rothwell &lt;sfr@canb.auug.org.au&gt;
Reported-by: kernel test robot &lt;lkp@intel.com&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Link: https://lkml.kernel.org/r/20210114111814.5346-1-bp@alien8.de
</pre>
</div>
</content>
</entry>
</feed>
