Merge tag 'v6.12.49-rt13' into dev/cawong/merge_25Q4_i10

v6.12.49-rt13

Signed-off-by: Can Wong <[email protected]>

Author: usercw88

Documentation/ABI/testing/sysfs-devices-system-cpu

@@ -525,6 +525,7 @@ What:		/sys/devices/system/cpu/vulnerabilities
 		/sys/devices/system/cpu/vulnerabilities/srbds
 		/sys/devices/system/cpu/vulnerabilities/tsa
 		/sys/devices/system/cpu/vulnerabilities/tsx_async_abort
+		/sys/devices/system/cpu/vulnerabilities/vmscape
 Date:		January 2018
 Contact:	Linux kernel mailing list <[email protected]>
 Description:	Information about CPU vulnerabilities

Documentation/admin-guide/hw-vuln/index.rst

@@ -23,3 +23,4 @@ are configurable at compile, boot or run time.
    gather_data_sampling
    reg-file-data-sampling
    indirect-target-selection
+   vmscape

Documentation/admin-guide/hw-vuln/srso.rst

@@ -104,7 +104,20 @@ The possible values in this file are:
 
    (spec_rstack_overflow=ibpb-vmexit)
 
+ * 'Mitigation: Reduced Speculation':
 
+   This mitigation gets automatically enabled when the above one "IBPB on
+   VMEXIT" has been selected and the CPU supports the BpSpecReduce bit.
+
+   It gets automatically enabled on machines which have the
+   SRSO_USER_KERNEL_NO=1 CPUID bit. In that case, the code logic is to switch
+   to the above =ibpb-vmexit mitigation because the user/kernel boundary is
+   not affected anymore and thus "safe RET" is not needed.
+
+   After enabling the IBPB on VMEXIT mitigation option, the BpSpecReduce bit
+   is detected (functionality present on all such machines) and that
+   practically overrides IBPB on VMEXIT as it has a lot less performance
+   impact and takes care of the guest->host attack vector too.
 
 In order to exploit vulnerability, an attacker needs to:
 

Documentation/admin-guide/hw-vuln/vmscape.rst

@@ -0,0 +1,110 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+VMSCAPE
+=======
+
+VMSCAPE is a vulnerability that may allow a guest to influence the branch
+prediction in host userspace. It particularly affects hypervisors like QEMU.
+
+Even if a hypervisor may not have any sensitive data like disk encryption keys,
+guest-userspace may be able to attack the guest-kernel using the hypervisor as
+a confused deputy.
+
+Affected processors
+-------------------
+
+The following CPU families are affected by VMSCAPE:
+
+**Intel processors:**
+  - Skylake generation (Parts without Enhanced-IBRS)
+  - Cascade Lake generation - (Parts affected by ITS guest/host separation)
+  - Alder Lake and newer (Parts affected by BHI)
+
+Note that, BHI affected parts that use BHB clearing software mitigation e.g.
+Icelake are not vulnerable to VMSCAPE.
+
+**AMD processors:**
+  - Zen series (families 0x17, 0x19, 0x1a)
+
+** Hygon processors:**
+ - Family 0x18
+
+Mitigation
+----------
+
+Conditional IBPB
+----------------
+
+Kernel tracks when a CPU has run a potentially malicious guest and issues an
+IBPB before the first exit to userspace after VM-exit. If userspace did not run
+between VM-exit and the next VM-entry, no IBPB is issued.
+
+Note that the existing userspace mitigation against Spectre-v2 is effective in
+protecting the userspace. They are insufficient to protect the userspace VMMs
+from a malicious guest. This is because Spectre-v2 mitigations are applied at
+context switch time, while the userspace VMM can run after a VM-exit without a
+context switch.
+
+Vulnerability enumeration and mitigation is not applied inside a guest. This is
+because nested hypervisors should already be deploying IBPB to isolate
+themselves from nested guests.
+
+SMT considerations
+------------------
+
+When Simultaneous Multi-Threading (SMT) is enabled, hypervisors can be
+vulnerable to cross-thread attacks. For complete protection against VMSCAPE
+attacks in SMT environments, STIBP should be enabled.
+
+The kernel will issue a warning if SMT is enabled without adequate STIBP
+protection. Warning is not issued when:
+
+- SMT is disabled
+- STIBP is enabled system-wide
+- Intel eIBRS is enabled (which implies STIBP protection)
+
+System information and options
+------------------------------
+
+The sysfs file showing VMSCAPE mitigation status is:
+
+  /sys/devices/system/cpu/vulnerabilities/vmscape
+
+The possible values in this file are:
+
+ * 'Not affected':
+
+   The processor is not vulnerable to VMSCAPE attacks.
+
+ * 'Vulnerable':
+
+   The processor is vulnerable and no mitigation has been applied.
+
+ * 'Mitigation: IBPB before exit to userspace':
+
+   Conditional IBPB mitigation is enabled. The kernel tracks when a CPU has
+   run a potentially malicious guest and issues an IBPB before the first
+   exit to userspace after VM-exit.
+
+ * 'Mitigation: IBPB on VMEXIT':
+
+   IBPB is issued on every VM-exit. This occurs when other mitigations like
+   RETBLEED or SRSO are already issuing IBPB on VM-exit.
+
+Mitigation control on the kernel command line
+----------------------------------------------
+
+The mitigation can be controlled via the ``vmscape=`` command line parameter:
+
+ * ``vmscape=off``:
+
+   Disable the VMSCAPE mitigation.
+
+ * ``vmscape=ibpb``:
+
+   Enable conditional IBPB mitigation (default when CONFIG_MITIGATION_VMSCAPE=y).
+
+ * ``vmscape=force``:
+
+   Force vulnerability detection and mitigation even on processors that are
+   not known to be affected.

Documentation/admin-guide/kernel-parameters.txt

@@ -3548,6 +3548,7 @@
 					       srbds=off [X86,INTEL]
 					       ssbd=force-off [ARM64]
 					       tsx_async_abort=off [X86]
+					       vmscape=off [X86]
 
 				Exceptions:
 					       This does not have any effect on
@@ -7425,6 +7426,16 @@
 	vmpoff=		[KNL,S390] Perform z/VM CP command after power off.
 			Format: <command>
 
+	vmscape=	[X86] Controls mitigation for VMscape attacks.
+			VMscape attacks can leak information from a userspace
+			hypervisor to a guest via speculative side-channels.
+
+			off		- disable the mitigation
+			ibpb		- use Indirect Branch Prediction Barrier
+					  (IBPB) mitigation (default)
+			force		- force vulnerability detection even on
+					  unaffected processors
+
 	vsyscall=	[X86-64,EARLY]
 			Controls the behavior of vsyscalls (i.e. calls to
 			fixed addresses of 0xffffffffff600x00 from legacy

Documentation/devicetree/bindings/display/msm/qcom,mdp5.yaml

@@ -60,7 +60,6 @@ properties:
           - const: bus
           - const: core
           - const: vsync
-          - const: lut
           - const: tbu
           - const: tbu_rt
         # MSM8996 has additional iommu clock

Documentation/devicetree/bindings/display/sprd/sprd,sharkl3-dpu.yaml

@@ -25,7 +25,7 @@ properties:
     maxItems: 1
 
   clocks:
-    minItems: 2
+    maxItems: 2
 
   clock-names:
     items:

Documentation/devicetree/bindings/display/sprd/sprd,sharkl3-dsi-host.yaml

@@ -20,7 +20,7 @@ properties:
     maxItems: 2
 
   clocks:
-    minItems: 1
+    maxItems: 1
 
   clock-names:
     items:

Documentation/devicetree/bindings/serial/brcm,bcm7271-uart.yaml

@@ -41,7 +41,7 @@ properties:
           - const: dma_intr2
 
   clocks:
-    minItems: 1
+    maxItems: 1
 
   clock-names:
     const: sw_baud

Documentation/devicetree/bindings/ufs/mediatek,ufs.yaml

@@ -33,6 +33,10 @@ properties:
 
   vcc-supply: true
 
+  mediatek,ufs-disable-mcq:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description: The mask to disable MCQ (Multi-Circular Queue) for UFS host.
+
 required:
   - compatible
   - clocks