Merge tag ' https://github.com/oupton/linux tags/kvmarm-6.3' from into kvmarm-master/next

Merge Oliver's kvmarm-6.3 tag:

KVM/arm64 updates for 6.3

 - Provide a virtual cache topology to the guest to avoid
   inconsistencies with migration on heterogenous systems. Non secure
   software has no practical need to traverse the caches by set/way in
   the first place.

 - Add support for taking stage-2 access faults in parallel. This was an
   accidental omission in the original parallel faults implementation,
   but should provide a marginal improvement to machines w/o FEAT_HAFDBS
   (such as hardware from the fruit company).

 - A preamble to adding support for nested virtualization to KVM,
   including vEL2 register state, rudimentary nested exception handling
   and masking unsupported features for nested guests.

 - Fixes to the PSCI relay that avoid an unexpected host SVE trap when
   resuming a CPU when running pKVM.

 - VGIC maintenance interrupt support for the AIC

 - Improvements to the arch timer emulation, primarily aimed at reducing
   the trap overhead of running nested.

 - Add CONFIG_USERFAULTFD to the KVM selftests config fragment in the
   interest of CI systems.

 - Avoid VM-wide stop-the-world operations when a vCPU accesses its own
   redistributor.

 - Serialize when toggling CPACR_EL1.SMEN to avoid unexpected exceptions
   in the host.

 - Aesthetic and comment/kerneldoc fixes

 - Drop the vestiges of the old Columbia mailing list and add myself as
   co-maintainer

This also drags in a couple of branches to avoid conflicts:

 - The shared 'kvm-hw-enable-refactor' branch that reworks
   initialization, as it conflicted with the virtual cache topology
   changes.

 - arm64's 'for-next/sme2' branch, as the PSCI relay changes, as both
   touched the EL2 initialization code.

Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Marc Zyngier

Documentation/admin-guide/kernel-parameters.txt

@@ -2553,9 +2553,14 @@
 			protected: nVHE-based mode with support for guests whose
 				   state is kept private from the host.
 
+			nested: VHE-based mode with support for nested
+				virtualization. Requires at least ARMv8.3
+				hardware.
+
 			Defaults to VHE/nVHE based on hardware support. Setting
 			mode to "protected" will disable kexec and hibernation
-			for the host.
+			for the host. "nested" is experimental and should be
+			used with extreme caution.
 
 	kvm-arm.vgic_v3_group0_trap=
 			[KVM,ARM] Trap guest accesses to GICv3 group-0

Documentation/arm64/booting.rst

@@ -369,6 +369,16 @@ Before jumping into the kernel, the following conditions must be met:
 
     - HCR_EL2.ATA (bit 56) must be initialised to 0b1.
 
+  For CPUs with the Scalable Matrix Extension version 2 (FEAT_SME2):
+
+  - If EL3 is present:
+
+    - SMCR_EL3.EZT0 (bit 30) must be initialised to 0b1.
+
+ - If the kernel is entered at EL1 and EL2 is present:
+
+    - SMCR_EL2.EZT0 (bit 30) must be initialised to 0b1.
+
 The requirements described above for CPU mode, caches, MMUs, architected
 timers, coherency and system registers apply to all CPUs.  All CPUs must
 enter the kernel in the same exception level.  Where the values documented

Documentation/arm64/elf_hwcaps.rst

@@ -284,6 +284,24 @@ HWCAP2_RPRFM
 HWCAP2_SVE2P1
     Functionality implied by ID_AA64ZFR0_EL1.SVEver == 0b0010.
 
+HWCAP2_SME2
+    Functionality implied by ID_AA64SMFR0_EL1.SMEver == 0b0001.
+
+HWCAP2_SME2P1
+    Functionality implied by ID_AA64SMFR0_EL1.SMEver == 0b0010.
+
+HWCAP2_SMEI16I32
+    Functionality implied by ID_AA64SMFR0_EL1.I16I32 == 0b0101
+
+HWCAP2_SMEBI32I32
+    Functionality implied by ID_AA64SMFR0_EL1.BI32I32 == 0b1
+
+HWCAP2_SMEB16B16
+    Functionality implied by ID_AA64SMFR0_EL1.B16B16 == 0b1
+
+HWCAP2_SMEF16F16
+    Functionality implied by ID_AA64SMFR0_EL1.F16F16 == 0b1
+
 4. Unused AT_HWCAP bits
 -----------------------
 

Documentation/arm64/sme.rst

@@ -18,14 +18,19 @@ model features for SME is included in Appendix A.
 1.  General
 -----------
 
-* PSTATE.SM, PSTATE.ZA, the streaming mode vector length, the ZA
-  register state and TPIDR2_EL0 are tracked per thread.
+* PSTATE.SM, PSTATE.ZA, the streaming mode vector length, the ZA and (when
+  present) ZTn register state and TPIDR2_EL0 are tracked per thread.
 
 * The presence of SME is reported to userspace via HWCAP2_SME in the aux vector
   AT_HWCAP2 entry.  Presence of this flag implies the presence of the SME
   instructions and registers, and the Linux-specific system interfaces
   described in this document.  SME is reported in /proc/cpuinfo as "sme".
 
+* The presence of SME2 is reported to userspace via HWCAP2_SME2 in the
+  aux vector AT_HWCAP2 entry.  Presence of this flag implies the presence of
+  the SME2 instructions and ZT0, and the Linux-specific system interfaces
+  described in this document.  SME2 is reported in /proc/cpuinfo as "sme2".
+
 * Support for the execution of SME instructions in userspace can also be
   detected by reading the CPU ID register ID_AA64PFR1_EL1 using an MRS
   instruction, and checking that the value of the SME field is nonzero. [3]
@@ -44,6 +49,7 @@ model features for SME is included in Appendix A.
 	HWCAP2_SME_B16F32
 	HWCAP2_SME_F32F32
 	HWCAP2_SME_FA64
+        HWCAP2_SME2
 
   This list may be extended over time as the SME architecture evolves.
 
@@ -52,8 +58,8 @@ model features for SME is included in Appendix A.
   cpu-feature-registers.txt for details.
 
 * Debuggers should restrict themselves to interacting with the target via the
-  NT_ARM_SVE, NT_ARM_SSVE and NT_ARM_ZA regsets.  The recommended way
-  of detecting support for these regsets is to connect to a target process
+  NT_ARM_SVE, NT_ARM_SSVE, NT_ARM_ZA and NT_ARM_ZT regsets.  The recommended
+  way of detecting support for these regsets is to connect to a target process
   first and then attempt a
 
 	ptrace(PTRACE_GETREGSET, pid, NT_ARM_<regset>, &iov).
@@ -89,13 +95,13 @@ be zeroed.
 -------------------------
 
 * On syscall PSTATE.ZA is preserved, if PSTATE.ZA==1 then the contents of the
-  ZA matrix are preserved.
+  ZA matrix and ZTn (if present) are preserved.
 
 * On syscall PSTATE.SM will be cleared and the SVE registers will be handled
   as per the standard SVE ABI.
 
-* Neither the SVE registers nor ZA are used to pass arguments to or receive
-  results from any syscall.
+* None of the SVE registers, ZA or ZTn are used to pass arguments to
+  or receive results from any syscall.
 
 * On process creation (eg, clone()) the newly created process will have
   PSTATE.SM cleared.
@@ -134,6 +140,14 @@ be zeroed.
   __reserved[] referencing this space.  za_context is then written in the
   extra space.  Refer to [1] for further details about this mechanism.
 
+* If ZTn is supported and PSTATE.ZA==1 then a signal frame record for ZTn will
+  be generated.
+
+* The signal record for ZTn has magic ZT_MAGIC (0x5a544e01) and consists of a
+  standard signal frame header followed by a struct zt_context specifying
+  the number of ZTn registers supported by the system, then zt_context.nregs
+  blocks of 64 bytes of data per register.
+
 
 5.  Signal return
 -----------------
@@ -151,6 +165,9 @@ When returning from a signal handler:
   the signal frame does not match the current vector length, the signal return
   attempt is treated as illegal, resulting in a forced SIGSEGV.
 
+* If ZTn is not supported or PSTATE.ZA==0 then it is illegal to have a
+  signal frame record for ZTn, resulting in a forced SIGSEGV.
+
 
 6.  prctl extensions
 --------------------
@@ -214,8 +231,8 @@ prctl(PR_SME_SET_VL, unsigned long arg)
       vector length that will be applied at the next execve() by the calling
       thread.
 
-    * Changing the vector length causes all of ZA, P0..P15, FFR and all bits of
-      Z0..Z31 except for Z0 bits [127:0] .. Z31 bits [127:0] to become
+    * Changing the vector length causes all of ZA, ZTn, P0..P15, FFR and all
+      bits of Z0..Z31 except for Z0 bits [127:0] .. Z31 bits [127:0] to become
       unspecified, including both streaming and non-streaming SVE state.
       Calling PR_SME_SET_VL with vl equal to the thread's current vector
       length, or calling PR_SME_SET_VL with the PR_SVE_SET_VL_ONEXEC flag,
@@ -317,6 +334,15 @@ The regset data starts with struct user_za_header, containing:
 
 * The effect of writing a partial, incomplete payload is unspecified.
 
+* A new regset NT_ARM_ZT is defined for access to ZTn state via
+  PTRACE_GETREGSET and PTRACE_SETREGSET.
+
+* The NT_ARM_ZT regset consists of a single 512 bit register.
+
+* When PSTATE.ZA==0 reads of NT_ARM_ZT will report all bits of ZTn as 0.
+
+* Writes to NT_ARM_ZT will set PSTATE.ZA to 1.
+
 
 8.  ELF coredump extensions
 ---------------------------
@@ -331,6 +357,11 @@ The regset data starts with struct user_za_header, containing:
   been read if a PTRACE_GETREGSET of NT_ARM_ZA were executed for each thread
   when the coredump was generated.
 
+* A NT_ARM_ZT note will be added to each coredump for each thread of the
+  dumped process.  The contents will be equivalent to the data that would have
+  been read if a PTRACE_GETREGSET of NT_ARM_ZT were executed for each thread
+  when the coredump was generated.
+
 * The NT_ARM_TLS note will be extended to two registers, the second register
   will contain TPIDR2_EL0 on systems that support SME and will be read as
   zero with writes ignored otherwise.
@@ -406,6 +437,9 @@ In A64 state, SME adds the following:
   For best system performance it is strongly encouraged for software to enable
   ZA only when it is actively being used.
 
+* A new ZT0 register is introduced when SME2 is present. This is a 512 bit
+  register which is accessible when PSTATE.ZA is set, as ZA itself is.
+
 * Two new 1 bit fields in PSTATE which may be controlled via the SMSTART and
   SMSTOP instructions or by access to the SVCR system register:
 

Documentation/virt/kvm/locking.rst

@@ -9,6 +9,8 @@ KVM Lock Overview
 
 The acquisition orders for mutexes are as follows:
 
+- cpus_read_lock() is taken outside kvm_lock
+
 - kvm->lock is taken outside vcpu->mutex
 
 - kvm->lock is taken outside kvm->slots_lock and kvm->irq_lock
@@ -226,15 +228,10 @@ time it will be set using the Dirty tracking mechanism described above.
 :Type:		mutex
 :Arch:		any
 :Protects:	- vm_list
-
-``kvm_count_lock``
-^^^^^^^^^^^^^^^^^^
-
-:Type:		raw_spinlock_t
-:Arch:		any
-:Protects:	- hardware virtualization enable/disable
-:Comment:	'raw' because hardware enabling/disabling must be atomic /wrt
-		migration.
+		- kvm_usage_count
+		- hardware virtualization enable/disable
+:Comment:	KVM also disables CPU hotplug via cpus_read_lock() during
+		enable/disable.
 
 ``kvm->mn_invalidate_lock``
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -292,3 +289,13 @@ time it will be set using the Dirty tracking mechanism described above.
 		wakeup notification event since external interrupts from the
 		assigned devices happens, we will find the vCPU on the list to
 		wakeup.
+
+``vendor_module_lock``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+:Type:		mutex
+:Arch:		x86
+:Protects:	loading a vendor module (kvm_amd or kvm_intel)
+:Comment:	Exists because using kvm_lock leads to deadlock.  cpu_hotplug_lock is
+    taken outside of kvm_lock, e.g. in KVM's CPU online/offline callbacks, and
+    many operations need to take cpu_hotplug_lock when loading a vendor module,
+    e.g. updating static calls.

MAINTAINERS

@@ -11355,13 +11355,12 @@ F:	virt/kvm/*
 
 KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)
 M:	Marc Zyngier <maz@kernel.org>
+M:	Oliver Upton <oliver.upton@linux.dev>
 R:	James Morse <james.morse@arm.com>
 R:	Suzuki K Poulose <suzuki.poulose@arm.com>
-R:	Oliver Upton <oliver.upton@linux.dev>
 R:	Zenghui Yu <yuzenghui@huawei.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 L:	kvmarm@lists.linux.dev
-L:	kvmarm@lists.cs.columbia.edu (deprecated, moderated for non-subscribers)
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git
 F:	arch/arm64/include/asm/kvm*

arch/arm64/include/asm/cache.h

@@ -16,6 +16,15 @@
 #define CLIDR_LOC(clidr)	(((clidr) >> CLIDR_LOC_SHIFT) & 0x7)
 #define CLIDR_LOUIS(clidr)	(((clidr) >> CLIDR_LOUIS_SHIFT) & 0x7)
 
+/* Ctypen, bits[3(n - 1) + 2 : 3(n - 1)], for n = 1 to 7 */
+#define CLIDR_CTYPE_SHIFT(level)	(3 * (level - 1))
+#define CLIDR_CTYPE_MASK(level)		(7 << CLIDR_CTYPE_SHIFT(level))
+#define CLIDR_CTYPE(clidr, level)	\
+	(((clidr) & CLIDR_CTYPE_MASK(level)) >> CLIDR_CTYPE_SHIFT(level))
+
+/* Ttypen, bits [2(n - 1) + 34 : 2(n - 1) + 33], for n = 1 to 7 */
+#define CLIDR_TTYPE_SHIFT(level)	(2 * ((level) - 1) + CLIDR_EL1_Ttypen_SHIFT)
+
 /*
  * Memory returned by kmalloc() may be used for DMA, so we must make
  * sure that all such allocations are cache aligned. Otherwise,

arch/arm64/include/asm/cpufeature.h

@@ -769,6 +769,12 @@ static __always_inline bool system_supports_sme(void)
 		cpus_have_const_cap(ARM64_SME);
 }
 
+static __always_inline bool system_supports_sme2(void)
+{
+	return IS_ENABLED(CONFIG_ARM64_SME) &&
+		cpus_have_const_cap(ARM64_SME2);
+}
+
 static __always_inline bool system_supports_fa64(void)
 {
 	return IS_ENABLED(CONFIG_ARM64_SME) &&

arch/arm64/include/asm/el2_setup.h

@@ -196,4 +196,103 @@
 	__init_el2_nvhe_prepare_eret
 .endm
 
+#ifndef __KVM_NVHE_HYPERVISOR__
+// This will clobber tmp1 and tmp2, and expect tmp1 to contain
+// the id register value as read from the HW
+.macro __check_override idreg, fld, width, pass, fail, tmp1, tmp2
+	ubfx	\tmp1, \tmp1, #\fld, #\width
+	cbz	\tmp1, \fail
+
+	adr_l	\tmp1, \idreg\()_override
+	ldr	\tmp2, [\tmp1, FTR_OVR_VAL_OFFSET]
+	ldr	\tmp1, [\tmp1, FTR_OVR_MASK_OFFSET]
+	ubfx	\tmp2, \tmp2, #\fld, #\width
+	ubfx	\tmp1, \tmp1, #\fld, #\width
+	cmp	\tmp1, xzr
+	and	\tmp2, \tmp2, \tmp1
+	csinv	\tmp2, \tmp2, xzr, ne
+	cbnz	\tmp2, \pass
+	b	\fail
+.endm
+
+// This will clobber tmp1 and tmp2
+.macro check_override idreg, fld, pass, fail, tmp1, tmp2
+	mrs	\tmp1, \idreg\()_el1
+	__check_override \idreg \fld 4 \pass \fail \tmp1 \tmp2
+.endm
+#else
+// This will clobber tmp
+.macro __check_override idreg, fld, width, pass, fail, tmp, ignore
+	ldr_l	\tmp, \idreg\()_el1_sys_val
+	ubfx	\tmp, \tmp, #\fld, #\width
+	cbnz	\tmp, \pass
+	b	\fail
+.endm
+
+.macro check_override idreg, fld, pass, fail, tmp, ignore
+	__check_override \idreg \fld 4 \pass \fail \tmp \ignore
+.endm
+#endif
+
+.macro finalise_el2_state
+	check_override id_aa64pfr0, ID_AA64PFR0_EL1_SVE_SHIFT, .Linit_sve_\@, .Lskip_sve_\@, x1, x2
+
+.Linit_sve_\@:	/* SVE register access */
+	mrs	x0, cptr_el2			// Disable SVE traps
+	bic	x0, x0, #CPTR_EL2_TZ
+	msr	cptr_el2, x0
+	isb
+	mov	x1, #ZCR_ELx_LEN_MASK		// SVE: Enable full vector
+	msr_s	SYS_ZCR_EL2, x1			// length for EL1.
+
+.Lskip_sve_\@:
+	check_override id_aa64pfr1, ID_AA64PFR1_EL1_SME_SHIFT, .Linit_sme_\@, .Lskip_sme_\@, x1, x2
+
+.Linit_sme_\@:	/* SME register access and priority mapping */
+	mrs	x0, cptr_el2			// Disable SME traps
+	bic	x0, x0, #CPTR_EL2_TSM
+	msr	cptr_el2, x0
+	isb
+
+	mrs	x1, sctlr_el2
+	orr	x1, x1, #SCTLR_ELx_ENTP2	// Disable TPIDR2 traps
+	msr	sctlr_el2, x1
+	isb
+
+	mov	x0, #0				// SMCR controls
+
+	// Full FP in SM?
+	mrs_s	x1, SYS_ID_AA64SMFR0_EL1
+	__check_override id_aa64smfr0, ID_AA64SMFR0_EL1_FA64_SHIFT, 1, .Linit_sme_fa64_\@, .Lskip_sme_fa64_\@, x1, x2
+
+.Linit_sme_fa64_\@:
+	orr	x0, x0, SMCR_ELx_FA64_MASK
+.Lskip_sme_fa64_\@:
+
+	// ZT0 available?
+	mrs_s	x1, SYS_ID_AA64SMFR0_EL1
+	__check_override id_aa64smfr0, ID_AA64SMFR0_EL1_SMEver_SHIFT, 4, .Linit_sme_zt0_\@, .Lskip_sme_zt0_\@, x1, x2
+.Linit_sme_zt0_\@:
+	orr	x0, x0, SMCR_ELx_EZT0_MASK
+.Lskip_sme_zt0_\@:
+
+	orr	x0, x0, #SMCR_ELx_LEN_MASK	// Enable full SME vector
+	msr_s	SYS_SMCR_EL2, x0		// length for EL1.
+
+	mrs_s	x1, SYS_SMIDR_EL1		// Priority mapping supported?
+	ubfx    x1, x1, #SMIDR_EL1_SMPS_SHIFT, #1
+	cbz     x1, .Lskip_sme_\@
+
+	msr_s	SYS_SMPRIMAP_EL2, xzr		// Make all priorities equal
+
+	mrs	x1, id_aa64mmfr1_el1		// HCRX_EL2 present?
+	ubfx	x1, x1, #ID_AA64MMFR1_EL1_HCX_SHIFT, #4
+	cbz	x1, .Lskip_sme_\@
+
+	mrs_s	x1, SYS_HCRX_EL2
+	orr	x1, x1, #HCRX_EL2_SMPME_MASK	// Enable priority mapping
+	msr_s	SYS_HCRX_EL2, x1
+.Lskip_sme_\@:
+.endm
+
 #endif /* __ARM_KVM_INIT_H__ */

arch/arm64/include/asm/esr.h

@@ -272,6 +272,10 @@
 		(((e) & ESR_ELx_SYS64_ISS_OP2_MASK) >>		\
 		 ESR_ELx_SYS64_ISS_OP2_SHIFT))
 
+/* ISS field definitions for ERET/ERETAA/ERETAB trapping */
+#define ESR_ELx_ERET_ISS_ERET		0x2
+#define ESR_ELx_ERET_ISS_ERETA		0x1
+
 /*
  * ISS field definitions for floating-point exception traps
  * (FP_EXC_32/FP_EXC_64).
@@ -350,6 +354,7 @@
 #define ESR_ELx_SME_ISS_ILL		1
 #define ESR_ELx_SME_ISS_SM_DISABLED	2
 #define ESR_ELx_SME_ISS_ZA_DISABLED	3
+#define ESR_ELx_SME_ISS_ZT_DISABLED	4
 
 #ifndef __ASSEMBLY__
 #include <asm/types.h>