[PATCH v3 00/21] arm64: Support for 2023 DPISA extensions

[PATCH v3 00/21] arm64: Support for 2023 DPISA extensions

[Mark Brown]

This series enables support for the data processing extensions in the
newly released 2023 architecture, this is mainly support for 8 bit
floating point formats.  Most of the extensions only introduce new
instructions and therefore only require hwcaps but there is a new EL0
visible control register FPMR used to control the 8 bit floating point
formats, we need to manage traps for this and context switch it.

The sharing of floating point save code between the host and guest
kernels slightly complicates the introduction of KVM support, we first
introduce host support with some placeholders for KVM then replace those
with the actual KVM support.

I've not added test coverage for ptrace, I've got a not quite finished
test program which exercises all the FP ptrace interfaces and their
interactions together, my plan is to cover it there rather than add
another tiny test program that duplicates the boilerplace for tracing a
target and doesn't actually run the traced program.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
Changes in v3:
- Rebase onto v6.7-rc3.
- Hook up traps for FPMR in emulate-nested.c.
- Link to v2: https://lore.kernel.org/r/20231114-arm64-2023-dpisa-v2-0-47251894f6a8@kernel.org

Changes in v2:
- Rebase onto v6.7-rc1.
- Link to v1: https://lore.kernel.org/r/20231026-arm64-2023-dpisa-v1-0-8470dd989bb2@kernel.org

---
Mark Brown (21):
      arm64/sysreg: Add definition for ID_AA64PFR2_EL1
      arm64/sysreg: Update ID_AA64ISAR2_EL1 defintion for DDI0601 2023-09
      arm64/sysreg: Add definition for ID_AA64ISAR3_EL1
      arm64/sysreg: Add definition for ID_AA64FPFR0_EL1
      arm64/sysreg: Update ID_AA64SMFR0_EL1 definition for DDI0601 2023-09
      arm64/sysreg: Update SCTLR_EL1 for DDI0601 2023-09
      arm64/sysreg: Update HCRX_EL2 definition for DDI0601 2023-09
      arm64/sysreg: Add definition for FPMR
      arm64/cpufeature: Hook new identification registers up to cpufeature
      arm64/fpsimd: Enable host kernel access to FPMR
      arm64/fpsimd: Support FEAT_FPMR
      arm64/signal: Add FPMR signal handling
      arm64/ptrace: Expose FPMR via ptrace
      KVM: arm64: Add newly allocated ID registers to register descriptions
      KVM: arm64: Support FEAT_FPMR for guests
      arm64/hwcap: Define hwcaps for 2023 DPISA features
      kselftest/arm64: Handle FPMR context in generic signal frame parser
      kselftest/arm64: Add basic FPMR test
      kselftest/arm64: Add 2023 DPISA hwcap test coverage
      KVM: arm64: selftests: Document feature registers added in 2023 extensions
      KVM: arm64: selftests: Teach get-reg-list about FPMR

 Documentation/arch/arm64/elf_hwcaps.rst            |  49 +++++
 arch/arm64/include/asm/cpu.h                       |   3 +
 arch/arm64/include/asm/cpufeature.h                |   5 +
 arch/arm64/include/asm/fpsimd.h                    |   2 +
 arch/arm64/include/asm/hwcap.h                     |  15 ++
 arch/arm64/include/asm/kvm_arm.h                   |   4 +-
 arch/arm64/include/asm/kvm_host.h                  |   3 +
 arch/arm64/include/asm/processor.h                 |   2 +
 arch/arm64/include/uapi/asm/hwcap.h                |  15 ++
 arch/arm64/include/uapi/asm/sigcontext.h           |   8 +
 arch/arm64/kernel/cpufeature.c                     |  72 +++++++
 arch/arm64/kernel/cpuinfo.c                        |  18 ++
 arch/arm64/kernel/fpsimd.c                         |  13 ++
 arch/arm64/kernel/ptrace.c                         |  42 ++++
 arch/arm64/kernel/signal.c                         |  59 ++++++
 arch/arm64/kvm/emulate-nested.c                    |   9 +
 arch/arm64/kvm/fpsimd.c                            |  19 +-
 arch/arm64/kvm/hyp/include/hyp/switch.h            |   7 +-
 arch/arm64/kvm/sys_regs.c                          |  17 +-
 arch/arm64/tools/cpucaps                           |   1 +
 arch/arm64/tools/sysreg                            | 153 ++++++++++++++-
 include/uapi/linux/elf.h                           |   1 +
 tools/testing/selftests/arm64/abi/hwcap.c          | 217 +++++++++++++++++++++
 tools/testing/selftests/arm64/signal/.gitignore    |   1 +
 .../arm64/signal/testcases/fpmr_siginfo.c          |  82 ++++++++
 .../selftests/arm64/signal/testcases/testcases.c   |   8 +
 .../selftests/arm64/signal/testcases/testcases.h   |   1 +
 tools/testing/selftests/kvm/aarch64/get-reg-list.c |  11 +-
 28 files changed, 819 insertions(+), 18 deletions(-)
---
base-commit: 2cc14f52aeb78ce3f29677c2de1f06c0e91471ab
change-id: 20231003-arm64-2023-dpisa-2f3d25746474

Best regards,
-- 
Mark Brown <broonie@kernel.org>


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[PATCH v3 01/21] arm64/sysreg: Add definition for ID_AA64PFR2_EL1

[Mark Brown]

DDI0601 2023-09 defines a new system register ID_AA64PFR2_EL1 which
enumerates FPMR and some new MTE features. Add a definition of this
register.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/tools/sysreg | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index 96cbeeab4eec..f22ade8f1fa7 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -1002,6 +1002,27 @@ UnsignedEnum	3:0	BT
 EndEnum
 EndSysreg
 
+Sysreg	ID_AA64PFR2_EL1	3	0	0	4	2
+Res0	63:36
+UnsignedEnum	35:32	FPMR
+	0b0000	NI
+	0b0001	IMP
+EndEnum
+Res0	31:12
+UnsignedEnum	11:8	MTEFAR
+	0b0000	NI
+	0b0001	IMP
+EndEnum
+UnsignedEnum	7:4	MTESTOREONLY
+	0b0000	NI
+	0b0001	IMP
+EndEnum
+UnsignedEnum	3:0	MTEPERM
+	0b0000	NI
+	0b0001	IMP
+EndEnum
+EndSysreg
+
 Sysreg	ID_AA64ZFR0_EL1	3	0	0	4	4
 Res0	63:60
 UnsignedEnum	59:56	F64MM

-- 
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[PATCH v3 02/21] arm64/sysreg: Update ID_AA64ISAR2_EL1 defintion for DDI0601 2023-09

[Mark Brown]

DDI0601 2023-09 defines some new fields in previously RES0 space in
ID_AA64ISAR2_EL1, together with one new enum value. Update the system
register definition to reflect this.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/tools/sysreg | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index f22ade8f1fa7..27d79644e1a0 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -1365,7 +1365,14 @@ EndEnum
 EndSysreg
 
 Sysreg	ID_AA64ISAR2_EL1	3	0	0	6	2
-Res0	63:56
+UnsignedEnum	63:60	ATS1A
+	0b0000	NI
+	0b0001	IMP
+EndEnum
+UnsignedEnum	59:56	LUT
+	0b0000	NI
+	0b0001	IMP
+EndEnum
 UnsignedEnum	55:52	CSSC
 	0b0000	NI
 	0b0001	IMP
@@ -1374,7 +1381,19 @@ UnsignedEnum	51:48	RPRFM
 	0b0000	NI
 	0b0001	IMP
 EndEnum
-Res0	47:32
+Res0	47:44
+UnsignedEnum	43:40	PRFMSLC
+	0b0000	NI
+	0b0001	IMP
+EndEnum
+UnsignedEnum	39:36	SYSINSTR_128
+	0b0000	NI
+	0b0001	IMP
+EndEnum
+UnsignedEnum	35:32	SYSREG_128
+	0b0000	NI
+	0b0001	IMP
+EndEnum
 UnsignedEnum	31:28	CLRBHB
 	0b0000	NI
 	0b0001	IMP
@@ -1398,6 +1417,7 @@ UnsignedEnum	15:12	APA3
 	0b0011	PAuth2
 	0b0100	FPAC
 	0b0101	FPACCOMBINE
+	0b0110	PAUTH_LR
 EndEnum
 UnsignedEnum	11:8	GPA3
 	0b0000	NI

-- 
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[PATCH v3 03/21] arm64/sysreg: Add definition for ID_AA64ISAR3_EL1

[Mark Brown]

DDI0601 2023-09 adds a new system register ID_AA64ISAR3_EL1 enumerating
new floating point and TLB invalidation features. Add a defintion for it.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/tools/sysreg | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index 27d79644e1a0..3d623a04934c 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -1433,6 +1433,23 @@ UnsignedEnum	3:0	WFxT
 EndEnum
 EndSysreg
 
+Sysreg	ID_AA64ISAR3_EL1	3	0	0	6	3
+Res0	63:12
+UnsignedEnum	11:8	TLBIW
+	0b0000	NI
+	0b0001	IMP
+EndEnum
+UnsignedEnum	7:4	FAMINMAX
+	0b0000	NI
+	0b0001	IMP
+EndEnum
+UnsignedEnum	3:0	CPA
+	0b0000	NI
+	0b0001	IMP
+	0b0010	CPA2
+EndEnum
+EndSysreg
+
 Sysreg	ID_AA64MMFR0_EL1	3	0	0	7	0
 UnsignedEnum	63:60	ECV
 	0b0000	NI

-- 
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[PATCH v3 04/21] arm64/sysreg: Add definition for ID_AA64FPFR0_EL1

[Mark Brown]

DDI0601 2023-09 defines a new feature register ID_AA64FPFR0_EL1 which
enumerates a number of FP8 related features. Add a definition for it.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/tools/sysreg | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index 3d623a04934c..c9bb49d0ea03 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -1131,6 +1131,35 @@ EndEnum
 Res0	31:0
 EndSysreg
 
+Sysreg	ID_AA64FPFR0_EL1	3	0	0	4	7
+Res0	63:32
+UnsignedEnum	31	F8CVT
+	0b0	NI
+	0b1	IMP
+EndEnum
+UnsignedEnum	30	F8FMA
+	0b0	NI
+	0b1	IMP
+EndEnum
+UnsignedEnum	29	F8DP4
+	0b0	NI
+	0b1	IMP
+EndEnum
+UnsignedEnum	28	F8DP2
+	0b0	NI
+	0b1	IMP
+EndEnum
+Res0	27:2
+UnsignedEnum	1	F8E4M3
+	0b0	NI
+	0b1	IMP
+EndEnum
+UnsignedEnum	0	F8E5M2
+	0b0	NI
+	0b1	IMP
+EndEnum
+EndSysreg
+
 Sysreg	ID_AA64DFR0_EL1	3	0	0	5	0
 Enum	63:60	HPMN0
 	0b0000	UNPREDICTABLE

-- 
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[PATCH v3 05/21] arm64/sysreg: Update ID_AA64SMFR0_EL1 definition for DDI0601 2023-09

[Mark Brown]

The 2023-09 release of DDI0601 defines a number of new feature enumeration
fields in ID_AA64SMFR0_EL1. Add these fields.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/tools/sysreg | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index c9bb49d0ea03..aee9ab4087c1 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -1079,7 +1079,11 @@ UnsignedEnum	63	FA64
 	0b0	NI
 	0b1	IMP
 EndEnum
-Res0	62:60
+Res0	62:61
+UnsignedEnum	60	LUTv2
+	0b0	NI
+	0b1	IMP
+EndEnum
 UnsignedEnum	59:56	SMEver
 	0b0000	SME
 	0b0001	SME2
@@ -1107,7 +1111,14 @@ UnsignedEnum	42	F16F16
 	0b0	NI
 	0b1	IMP
 EndEnum
-Res0	41:40
+UnsignedEnum	41	F8F16
+	0b0	NI
+	0b1	IMP
+EndEnum
+UnsignedEnum	40	F8F32
+	0b0	NI
+	0b1	IMP
+EndEnum
 UnsignedEnum	39:36	I8I32
 	0b0000	NI
 	0b1111	IMP
@@ -1128,7 +1139,20 @@ UnsignedEnum	32	F32F32
 	0b0	NI
 	0b1	IMP
 EndEnum
-Res0	31:0
+Res0	31
+UnsignedEnum	30	SF8FMA
+	0b0	NI
+	0b1	IMP
+EndEnum
+UnsignedEnum	29	SF8DP4
+	0b0	NI
+	0b1	IMP
+EndEnum
+UnsignedEnum	28	SF8DP2
+	0b0	NI
+	0b1	IMP
+EndEnum
+Res0	27:0
 EndSysreg
 
 Sysreg	ID_AA64FPFR0_EL1	3	0	0	4	7

-- 
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[PATCH v3 06/21] arm64/sysreg: Update SCTLR_EL1 for DDI0601 2023-09

[Mark Brown]

DDI0601 2023-09 defines some new fields in SCTLR_EL1 controlling new MTE
and floating point features. Update our sysreg definition to reflect these.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/tools/sysreg | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index aee9ab4087c1..eea69bb48fa7 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -1791,7 +1791,8 @@ Field	63	TIDCP
 Field	62	SPINTMASK
 Field	61	NMI
 Field	60	EnTP2
-Res0	59:58
+Field	59	TCSO
+Field	58	TCSO0
 Field	57	EPAN
 Field	56	EnALS
 Field	55	EnAS0
@@ -1820,7 +1821,7 @@ EndEnum
 Field	37	ITFSB
 Field	36	BT1
 Field	35	BT0
-Res0	34
+Field	34	EnFPM
 Field	33	MSCEn
 Field	32	CMOW
 Field	31	EnIA

-- 
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[PATCH v3 07/21] arm64/sysreg: Update HCRX_EL2 definition for DDI0601 2023-09

[Mark Brown]

DDI0601 2023-09 defines new fields in HCRX_EL2 controlling access to new
system registers, update our definition of HCRX_EL2 to reflect this.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/tools/sysreg | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index eea69bb48fa7..0b1a33a77074 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -2412,7 +2412,9 @@ Fields	ZCR_ELx
 EndSysreg
 
 Sysreg	HCRX_EL2	3	4	1	2	2
-Res0	63:23
+Res0	63:25
+Field	24	PACMEn
+Field	23	EnFPM
 Field	22	GCSEn
 Field	21	EnIDCP128
 Field	20	EnSDERR

-- 
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[PATCH v3 08/21] arm64/sysreg: Add definition for FPMR

[Mark Brown]

DDI0601 2023-09 defines a new sysrem register FPMR (Floating Point Mode
Register) which configures the new FP8 features. Add a definition of this
register.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/tools/sysreg | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index 0b1a33a77074..67173576115a 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -2138,6 +2138,29 @@ Field	1	ZA
 Field	0	SM
 EndSysreg
 
+Sysreg	FPMR	3	3	4	4	2
+Res0	63:38
+Field	37:32	LSCALE2
+Field	31:24	NSCALE
+Res0	23
+Field	22:16	LSCALE
+Field	15	OSC
+Field	14	OSM
+Res0	13:9
+UnsignedEnum	8:6	F8D
+	0b000	E5M2
+	0b001	E4M3
+EndEnum
+UnsignedEnum	5:3	F8S2
+	0b000	E5M2
+	0b001	E4M3
+EndEnum
+UnsignedEnum	2:0	F8S1
+	0b000	E5M2
+	0b001	E4M3
+EndEnum
+EndSysreg
+
 SysregFields	HFGxTR_EL2
 Field	63	nAMAIR2_EL1
 Field	62	nMAIR2_EL1

-- 
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[PATCH v3 09/21] arm64/cpufeature: Hook new identification registers up to cpufeature

[Mark Brown]

The 2023 architecture extensions have defined several new ID registers,
hook them up to the cpufeature code so we can add feature checks and hwcaps
based on their contents.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/asm/cpu.h   |  3 +++
 arch/arm64/kernel/cpufeature.c | 28 ++++++++++++++++++++++++++++
 arch/arm64/kernel/cpuinfo.c    |  3 +++
 3 files changed, 34 insertions(+)

diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h
index f3034099fd95..b99138bc3d4a 100644
--- a/arch/arm64/include/asm/cpu.h
+++ b/arch/arm64/include/asm/cpu.h
@@ -53,14 +53,17 @@ struct cpuinfo_arm64 {
 	u64		reg_id_aa64isar0;
 	u64		reg_id_aa64isar1;
 	u64		reg_id_aa64isar2;
+	u64		reg_id_aa64isar3;
 	u64		reg_id_aa64mmfr0;
 	u64		reg_id_aa64mmfr1;
 	u64		reg_id_aa64mmfr2;
 	u64		reg_id_aa64mmfr3;
 	u64		reg_id_aa64pfr0;
 	u64		reg_id_aa64pfr1;
+	u64		reg_id_aa64pfr2;
 	u64		reg_id_aa64zfr0;
 	u64		reg_id_aa64smfr0;
+	u64		reg_id_aa64fpfr0;
 
 	struct cpuinfo_32bit	aarch32;
 };
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 646591c67e7a..c8d38e5ce997 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -234,6 +234,10 @@ static const struct arm64_ftr_bits ftr_id_aa64isar2[] = {
 	ARM64_FTR_END,
 };
 
+static const struct arm64_ftr_bits ftr_id_aa64isar3[] = {
+	ARM64_FTR_END,
+};
+
 static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = {
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_CSV3_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR0_EL1_CSV2_SHIFT, 4, 0),
@@ -267,6 +271,10 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
 	ARM64_FTR_END,
 };
 
+static const struct arm64_ftr_bits ftr_id_aa64pfr2[] = {
+	ARM64_FTR_END,
+};
+
 static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SVE),
 		       FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ZFR0_EL1_F64MM_SHIFT, 4, 0),
@@ -319,6 +327,10 @@ static const struct arm64_ftr_bits ftr_id_aa64smfr0[] = {
 	ARM64_FTR_END,
 };
 
+static const struct arm64_ftr_bits ftr_id_aa64fpfr0[] = {
+	ARM64_FTR_END,
+};
+
 static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_EL1_ECV_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_EL1_FGT_SHIFT, 4, 0),
@@ -702,10 +714,12 @@ static const struct __ftr_reg_entry {
 			       &id_aa64pfr0_override),
 	ARM64_FTR_REG_OVERRIDE(SYS_ID_AA64PFR1_EL1, ftr_id_aa64pfr1,
 			       &id_aa64pfr1_override),
+	ARM64_FTR_REG(SYS_ID_AA64PFR2_EL1, ftr_id_aa64pfr2),
 	ARM64_FTR_REG_OVERRIDE(SYS_ID_AA64ZFR0_EL1, ftr_id_aa64zfr0,
 			       &id_aa64zfr0_override),
 	ARM64_FTR_REG_OVERRIDE(SYS_ID_AA64SMFR0_EL1, ftr_id_aa64smfr0,
 			       &id_aa64smfr0_override),
+	ARM64_FTR_REG(SYS_ID_AA64FPFR0_EL1, ftr_id_aa64fpfr0),
 
 	/* Op1 = 0, CRn = 0, CRm = 5 */
 	ARM64_FTR_REG(SYS_ID_AA64DFR0_EL1, ftr_id_aa64dfr0),
@@ -717,6 +731,7 @@ static const struct __ftr_reg_entry {
 			       &id_aa64isar1_override),
 	ARM64_FTR_REG_OVERRIDE(SYS_ID_AA64ISAR2_EL1, ftr_id_aa64isar2,
 			       &id_aa64isar2_override),
+	ARM64_FTR_REG(SYS_ID_AA64ISAR3_EL1, ftr_id_aa64isar3),
 
 	/* Op1 = 0, CRn = 0, CRm = 7 */
 	ARM64_FTR_REG(SYS_ID_AA64MMFR0_EL1, ftr_id_aa64mmfr0),
@@ -1043,14 +1058,17 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
 	init_cpu_ftr_reg(SYS_ID_AA64ISAR0_EL1, info->reg_id_aa64isar0);
 	init_cpu_ftr_reg(SYS_ID_AA64ISAR1_EL1, info->reg_id_aa64isar1);
 	init_cpu_ftr_reg(SYS_ID_AA64ISAR2_EL1, info->reg_id_aa64isar2);
+	init_cpu_ftr_reg(SYS_ID_AA64ISAR3_EL1, info->reg_id_aa64isar3);
 	init_cpu_ftr_reg(SYS_ID_AA64MMFR0_EL1, info->reg_id_aa64mmfr0);
 	init_cpu_ftr_reg(SYS_ID_AA64MMFR1_EL1, info->reg_id_aa64mmfr1);
 	init_cpu_ftr_reg(SYS_ID_AA64MMFR2_EL1, info->reg_id_aa64mmfr2);
 	init_cpu_ftr_reg(SYS_ID_AA64MMFR3_EL1, info->reg_id_aa64mmfr3);
 	init_cpu_ftr_reg(SYS_ID_AA64PFR0_EL1, info->reg_id_aa64pfr0);
 	init_cpu_ftr_reg(SYS_ID_AA64PFR1_EL1, info->reg_id_aa64pfr1);
+	init_cpu_ftr_reg(SYS_ID_AA64PFR2_EL1, info->reg_id_aa64pfr2);
 	init_cpu_ftr_reg(SYS_ID_AA64ZFR0_EL1, info->reg_id_aa64zfr0);
 	init_cpu_ftr_reg(SYS_ID_AA64SMFR0_EL1, info->reg_id_aa64smfr0);
+	init_cpu_ftr_reg(SYS_ID_AA64FPFR0_EL1, info->reg_id_aa64fpfr0);
 
 	if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0))
 		init_32bit_cpu_features(&info->aarch32);
@@ -1291,6 +1309,8 @@ void update_cpu_features(int cpu,
 				      info->reg_id_aa64isar1, boot->reg_id_aa64isar1);
 	taint |= check_update_ftr_reg(SYS_ID_AA64ISAR2_EL1, cpu,
 				      info->reg_id_aa64isar2, boot->reg_id_aa64isar2);
+	taint |= check_update_ftr_reg(SYS_ID_AA64ISAR3_EL1, cpu,
+				      info->reg_id_aa64isar3, boot->reg_id_aa64isar3);
 
 	/*
 	 * Differing PARange support is fine as long as all peripherals and
@@ -1310,6 +1330,8 @@ void update_cpu_features(int cpu,
 				      info->reg_id_aa64pfr0, boot->reg_id_aa64pfr0);
 	taint |= check_update_ftr_reg(SYS_ID_AA64PFR1_EL1, cpu,
 				      info->reg_id_aa64pfr1, boot->reg_id_aa64pfr1);
+	taint |= check_update_ftr_reg(SYS_ID_AA64PFR2_EL1, cpu,
+				      info->reg_id_aa64pfr2, boot->reg_id_aa64pfr2);
 
 	taint |= check_update_ftr_reg(SYS_ID_AA64ZFR0_EL1, cpu,
 				      info->reg_id_aa64zfr0, boot->reg_id_aa64zfr0);
@@ -1317,6 +1339,9 @@ void update_cpu_features(int cpu,
 	taint |= check_update_ftr_reg(SYS_ID_AA64SMFR0_EL1, cpu,
 				      info->reg_id_aa64smfr0, boot->reg_id_aa64smfr0);
 
+	taint |= check_update_ftr_reg(SYS_ID_AA64FPFR0_EL1, cpu,
+				      info->reg_id_aa64fpfr0, boot->reg_id_aa64fpfr0);
+
 	/* Probe vector lengths */
 	if (IS_ENABLED(CONFIG_ARM64_SVE) &&
 	    id_aa64pfr0_sve(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1))) {
@@ -1429,8 +1454,10 @@ u64 __read_sysreg_by_encoding(u32 sys_id)
 
 	read_sysreg_case(SYS_ID_AA64PFR0_EL1);
 	read_sysreg_case(SYS_ID_AA64PFR1_EL1);
+	read_sysreg_case(SYS_ID_AA64PFR2_EL1);
 	read_sysreg_case(SYS_ID_AA64ZFR0_EL1);
 	read_sysreg_case(SYS_ID_AA64SMFR0_EL1);
+	read_sysreg_case(SYS_ID_AA64FPFR0_EL1);
 	read_sysreg_case(SYS_ID_AA64DFR0_EL1);
 	read_sysreg_case(SYS_ID_AA64DFR1_EL1);
 	read_sysreg_case(SYS_ID_AA64MMFR0_EL1);
@@ -1440,6 +1467,7 @@ u64 __read_sysreg_by_encoding(u32 sys_id)
 	read_sysreg_case(SYS_ID_AA64ISAR0_EL1);
 	read_sysreg_case(SYS_ID_AA64ISAR1_EL1);
 	read_sysreg_case(SYS_ID_AA64ISAR2_EL1);
+	read_sysreg_case(SYS_ID_AA64ISAR3_EL1);
 
 	read_sysreg_case(SYS_CNTFRQ_EL0);
 	read_sysreg_case(SYS_CTR_EL0);
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index a257da7b56fe..8322e968fd0d 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -448,14 +448,17 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
 	info->reg_id_aa64isar0 = read_cpuid(ID_AA64ISAR0_EL1);
 	info->reg_id_aa64isar1 = read_cpuid(ID_AA64ISAR1_EL1);
 	info->reg_id_aa64isar2 = read_cpuid(ID_AA64ISAR2_EL1);
+	info->reg_id_aa64isar3 = read_cpuid(ID_AA64ISAR3_EL1);
 	info->reg_id_aa64mmfr0 = read_cpuid(ID_AA64MMFR0_EL1);
 	info->reg_id_aa64mmfr1 = read_cpuid(ID_AA64MMFR1_EL1);
 	info->reg_id_aa64mmfr2 = read_cpuid(ID_AA64MMFR2_EL1);
 	info->reg_id_aa64mmfr3 = read_cpuid(ID_AA64MMFR3_EL1);
 	info->reg_id_aa64pfr0 = read_cpuid(ID_AA64PFR0_EL1);
 	info->reg_id_aa64pfr1 = read_cpuid(ID_AA64PFR1_EL1);
+	info->reg_id_aa64pfr2 = read_cpuid(ID_AA64PFR2_EL1);
 	info->reg_id_aa64zfr0 = read_cpuid(ID_AA64ZFR0_EL1);
 	info->reg_id_aa64smfr0 = read_cpuid(ID_AA64SMFR0_EL1);
+	info->reg_id_aa64fpfr0 = read_cpuid(ID_AA64FPFR0_EL1);
 
 	if (id_aa64pfr1_mte(info->reg_id_aa64pfr1))
 		info->reg_gmid = read_cpuid(GMID_EL1);

-- 
2.30.2


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[PATCH v3 10/21] arm64/fpsimd: Enable host kernel access to FPMR

[Mark Brown]

FEAT_FPMR provides a new generally accessible architectural register FPMR.
This is only accessible to EL0 and EL1 when HCRX_EL2.EnFPM is set to 1,
do this when the host is running. The guest part will be done along with
context switching the new register and exposing it via guest management.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/asm/kvm_arm.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index b85f46a73e21..9f9239d86900 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -105,7 +105,7 @@
 #define HCRX_GUEST_FLAGS \
 	(HCRX_EL2_SMPME | HCRX_EL2_TCR2En | \
 	 (cpus_have_final_cap(ARM64_HAS_MOPS) ? (HCRX_EL2_MSCEn | HCRX_EL2_MCE2) : 0))
-#define HCRX_HOST_FLAGS (HCRX_EL2_MSCEn | HCRX_EL2_TCR2En)
+#define HCRX_HOST_FLAGS (HCRX_EL2_MSCEn | HCRX_EL2_TCR2En | HCRX_EL2_EnFPM)
 
 /* TCR_EL2 Registers bits */
 #define TCR_EL2_RES1		((1U << 31) | (1 << 23))

-- 
2.30.2


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[PATCH v3 11/21] arm64/fpsimd: Support FEAT_FPMR

[Mark Brown]

FEAT_FPMR defines a new EL0 accessible register FPMR use to configure the
FP8 related features added to the architecture at the same time. Detect
support for this register and context switch it for EL0 when present.

Due to the sharing of responsibility for saving floating point state
between the host kernel and KVM FP8 support is not yet implemented in KVM
and a stub similar to that used for SVCR is provided for FPMR in order to
avoid bisection issues.  To make it easier to share host state with the
hypervisor we store FPMR immediately after the base floating point
state, existing usage means that it is not practical to extend that
directly.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/asm/cpufeature.h |  5 +++++
 arch/arm64/include/asm/fpsimd.h     |  2 ++
 arch/arm64/include/asm/kvm_host.h   |  1 +
 arch/arm64/include/asm/processor.h  |  2 ++
 arch/arm64/kernel/cpufeature.c      |  9 +++++++++
 arch/arm64/kernel/fpsimd.c          | 13 +++++++++++++
 arch/arm64/kvm/fpsimd.c             |  1 +
 arch/arm64/tools/cpucaps            |  1 +
 8 files changed, 34 insertions(+)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index f6d416fe49b0..8e83cb1e6c7c 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -767,6 +767,11 @@ static __always_inline bool system_supports_tpidr2(void)
 	return system_supports_sme();
 }
 
+static __always_inline bool system_supports_fpmr(void)
+{
+	return alternative_has_cap_unlikely(ARM64_HAS_FPMR);
+}
+
 static __always_inline bool system_supports_cnp(void)
 {
 	return alternative_has_cap_unlikely(ARM64_HAS_CNP);
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index 50e5f25d3024..74afca3bd312 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -89,6 +89,7 @@ struct cpu_fp_state {
 	void *sve_state;
 	void *sme_state;
 	u64 *svcr;
+	u64 *fpmr;
 	unsigned int sve_vl;
 	unsigned int sme_vl;
 	enum fp_type *fp_type;
@@ -154,6 +155,7 @@ extern void cpu_enable_sve(const struct arm64_cpu_capabilities *__unused);
 extern void cpu_enable_sme(const struct arm64_cpu_capabilities *__unused);
 extern void cpu_enable_sme2(const struct arm64_cpu_capabilities *__unused);
 extern void cpu_enable_fa64(const struct arm64_cpu_capabilities *__unused);
+extern void cpu_enable_fpmr(const struct arm64_cpu_capabilities *__unused);
 
 extern u64 read_smcr_features(void);
 
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 824f29f04916..f8d98985a39c 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -517,6 +517,7 @@ struct kvm_vcpu_arch {
 	enum fp_type fp_type;
 	unsigned int sve_max_vl;
 	u64 svcr;
+	u64 fpmr;
 
 	/* Stage 2 paging state used by the hardware on next switch */
 	struct kvm_s2_mmu *hw_mmu;
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index e5bc54522e71..dd3a5b29f76e 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -158,6 +158,8 @@ struct thread_struct {
 		struct user_fpsimd_state fpsimd_state;
 	} uw;
 
+	u64			fpmr;		/* Adjacent to fpsimd_state for KVM */
+
 	enum fp_type		fp_type;	/* registers FPSIMD or SVE? */
 	unsigned int		fpsimd_cpu;
 	void			*sve_state;	/* SVE registers, if any */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index c8d38e5ce997..ea0b680792de 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -272,6 +272,7 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64pfr2[] = {
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR2_EL1_FPMR_SHIFT, 4, 0),
 	ARM64_FTR_END,
 };
 
@@ -2759,6 +2760,14 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.matches = has_cpuid_feature,
 		ARM64_CPUID_FIELDS(ID_AA64MMFR2_EL1, EVT, IMP)
 	},
+	{
+		.desc = "FPMR",
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.capability = ARM64_HAS_FPMR,
+		.matches = has_cpuid_feature,
+		.cpu_enable = cpu_enable_fpmr,
+		ARM64_CPUID_FIELDS(ID_AA64PFR2_EL1, FPMR, IMP)
+	},
 	{},
 };
 
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 1559c706d32d..2a6abd6423f7 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -385,6 +385,9 @@ static void task_fpsimd_load(void)
 	WARN_ON(!system_supports_fpsimd());
 	WARN_ON(!have_cpu_fpsimd_context());
 
+	if (system_supports_fpmr())
+		write_sysreg_s(current->thread.fpmr, SYS_FPMR);
+
 	if (system_supports_sve() || system_supports_sme()) {
 		switch (current->thread.fp_type) {
 		case FP_STATE_FPSIMD:
@@ -472,6 +475,9 @@ static void fpsimd_save(void)
 	if (test_thread_flag(TIF_FOREIGN_FPSTATE))
 		return;
 
+	if (system_supports_fpmr())
+		*(last->fpmr) = read_sysreg_s(SYS_FPMR);
+
 	/*
 	 * If a task is in a syscall the ABI allows us to only
 	 * preserve the state shared with FPSIMD so don't bother
@@ -714,6 +720,12 @@ static void sve_to_fpsimd(struct task_struct *task)
 	}
 }
 
+void cpu_enable_fpmr(const struct arm64_cpu_capabilities *__always_unused p)
+{
+	write_sysreg_s(read_sysreg_s(SYS_SCTLR_EL1) | SCTLR_EL1_EnFPM_MASK,
+		       SYS_SCTLR_EL1);
+}
+
 #ifdef CONFIG_ARM64_SVE
 /*
  * Call __sve_free() directly only if you know task can't be scheduled
@@ -1671,6 +1683,7 @@ static void fpsimd_bind_task_to_cpu(void)
 	last->sve_vl = task_get_sve_vl(current);
 	last->sme_vl = task_get_sme_vl(current);
 	last->svcr = &current->thread.svcr;
+	last->fpmr = &current->thread.fpmr;
 	last->fp_type = &current->thread.fp_type;
 	last->to_save = FP_STATE_CURRENT;
 	current->thread.fpsimd_cpu = smp_processor_id();
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
index 8c1d0d4853df..e3e611e30e91 100644
--- a/arch/arm64/kvm/fpsimd.c
+++ b/arch/arm64/kvm/fpsimd.c
@@ -153,6 +153,7 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu)
 		fp_state.sve_vl = vcpu->arch.sve_max_vl;
 		fp_state.sme_state = NULL;
 		fp_state.svcr = &vcpu->arch.svcr;
+		fp_state.fpmr = &vcpu->arch.fpmr;
 		fp_state.fp_type = &vcpu->arch.fp_type;
 
 		if (vcpu_has_sve(vcpu))
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index b98c38288a9d..7a249a950bbc 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -26,6 +26,7 @@ HAS_ECV
 HAS_ECV_CNTPOFF
 HAS_EPAN
 HAS_EVT
+HAS_FPMR
 HAS_FGT
 HAS_FPSIMD
 HAS_GENERIC_AUTH

-- 
2.30.2


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[PATCH v3 12/21] arm64/signal: Add FPMR signal handling

[Mark Brown]

Expose FPMR in the signal context on systems where it is supported. The
kernel validates the exact size of the FPSIMD registers so we can't readily
add it to fpsimd_context without disruption.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/uapi/asm/sigcontext.h |  8 +++++
 arch/arm64/kernel/signal.c               | 59 ++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)

diff --git a/arch/arm64/include/uapi/asm/sigcontext.h b/arch/arm64/include/uapi/asm/sigcontext.h
index f23c1dc3f002..8a45b7a411e0 100644
--- a/arch/arm64/include/uapi/asm/sigcontext.h
+++ b/arch/arm64/include/uapi/asm/sigcontext.h
@@ -152,6 +152,14 @@ struct tpidr2_context {
 	__u64 tpidr2;
 };
 
+/* FPMR context */
+#define FPMR_MAGIC	0x46504d52
+
+struct fpmr_context {
+	struct _aarch64_ctx head;
+	__u64 fpmr;
+};
+
 #define ZA_MAGIC	0x54366345
 
 struct za_context {
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 0e8beb3349ea..e8c808afcc8a 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -60,6 +60,7 @@ struct rt_sigframe_user_layout {
 	unsigned long tpidr2_offset;
 	unsigned long za_offset;
 	unsigned long zt_offset;
+	unsigned long fpmr_offset;
 	unsigned long extra_offset;
 	unsigned long end_offset;
 };
@@ -182,6 +183,8 @@ struct user_ctxs {
 	u32 za_size;
 	struct zt_context __user *zt;
 	u32 zt_size;
+	struct fpmr_context __user *fpmr;
+	u32 fpmr_size;
 };
 
 static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
@@ -227,6 +230,33 @@ static int restore_fpsimd_context(struct user_ctxs *user)
 	return err ? -EFAULT : 0;
 }
 
+static int preserve_fpmr_context(struct fpmr_context __user *ctx)
+{
+	int err = 0;
+
+	current->thread.fpmr = read_sysreg_s(SYS_FPMR);
+
+	__put_user_error(FPMR_MAGIC, &ctx->head.magic, err);
+	__put_user_error(sizeof(*ctx), &ctx->head.size, err);
+	__put_user_error(current->thread.fpmr, &ctx->fpmr, err);
+
+	return err;
+}
+
+static int restore_fpmr_context(struct user_ctxs *user)
+{
+	u64 fpmr;
+	int err = 0;
+
+	if (user->fpmr_size != sizeof(*user->fpmr))
+		return -EINVAL;
+
+	__get_user_error(fpmr, &user->fpmr->fpmr, err);
+	if (!err)
+		write_sysreg_s(fpmr, SYS_FPMR);
+
+	return err;
+}
 
 #ifdef CONFIG_ARM64_SVE
 
@@ -590,6 +620,7 @@ static int parse_user_sigframe(struct user_ctxs *user,
 	user->tpidr2 = NULL;
 	user->za = NULL;
 	user->zt = NULL;
+	user->fpmr = NULL;
 
 	if (!IS_ALIGNED((unsigned long)base, 16))
 		goto invalid;
@@ -684,6 +715,17 @@ static int parse_user_sigframe(struct user_ctxs *user,
 			user->zt_size = size;
 			break;
 
+		case FPMR_MAGIC:
+			if (!system_supports_fpmr())
+				goto invalid;
+
+			if (user->fpmr)
+				goto invalid;
+
+			user->fpmr = (struct fpmr_context __user *)head;
+			user->fpmr_size = size;
+			break;
+
 		case EXTRA_MAGIC:
 			if (have_extra_context)
 				goto invalid;
@@ -806,6 +848,9 @@ static int restore_sigframe(struct pt_regs *regs,
 	if (err == 0 && system_supports_tpidr2() && user.tpidr2)
 		err = restore_tpidr2_context(&user);
 
+	if (err == 0 && system_supports_fpmr() && user.fpmr)
+		err = restore_fpmr_context(&user);
+
 	if (err == 0 && system_supports_sme() && user.za)
 		err = restore_za_context(&user);
 
@@ -928,6 +973,13 @@ static int setup_sigframe_layout(struct rt_sigframe_user_layout *user,
 		}
 	}
 
+	if (system_supports_fpmr()) {
+		err = sigframe_alloc(user, &user->fpmr_offset,
+				     sizeof(struct fpmr_context));
+		if (err)
+			return err;
+	}
+
 	return sigframe_alloc_end(user);
 }
 
@@ -983,6 +1035,13 @@ static int setup_sigframe(struct rt_sigframe_user_layout *user,
 		err |= preserve_tpidr2_context(tpidr2_ctx);
 	}
 
+	/* FPMR if supported */
+	if (system_supports_fpmr() && err == 0) {
+		struct fpmr_context __user *fpmr_ctx =
+			apply_user_offset(user, user->fpmr_offset);
+		err |= preserve_fpmr_context(fpmr_ctx);
+	}
+
 	/* ZA state if present */
 	if (system_supports_sme() && err == 0 && user->za_offset) {
 		struct za_context __user *za_ctx =

-- 
2.30.2


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[PATCH v3 13/21] arm64/ptrace: Expose FPMR via ptrace

[Mark Brown]

Add a new regset to expose FPMR via ptrace. It is not added to the FPSIMD
registers since that structure is exposed elsewhere without any allowance
for extension we don't add there.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/kernel/ptrace.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/elf.h   |  1 +
 2 files changed, 43 insertions(+)

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 20d7ef82de90..cfb8a4d213be 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -697,6 +697,39 @@ static int tls_set(struct task_struct *target, const struct user_regset *regset,
 	return ret;
 }
 
+static int fpmr_get(struct task_struct *target, const struct user_regset *regset,
+		   struct membuf to)
+{
+	if (!system_supports_fpmr())
+		return -EINVAL;
+
+	if (target == current)
+		fpsimd_preserve_current_state();
+
+	return membuf_store(&to, target->thread.fpmr);
+}
+
+static int fpmr_set(struct task_struct *target, const struct user_regset *regset,
+		   unsigned int pos, unsigned int count,
+		   const void *kbuf, const void __user *ubuf)
+{
+	int ret;
+	unsigned long fpmr;
+
+	if (!system_supports_fpmr())
+		return -EINVAL;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &fpmr, 0, count);
+	if (ret)
+		return ret;
+
+	target->thread.fpmr = fpmr;
+
+	fpsimd_flush_task_state(target);
+
+	return 0;
+}
+
 static int system_call_get(struct task_struct *target,
 			   const struct user_regset *regset,
 			   struct membuf to)
@@ -1417,6 +1450,7 @@ enum aarch64_regset {
 	REGSET_HW_BREAK,
 	REGSET_HW_WATCH,
 #endif
+	REGSET_FPMR,
 	REGSET_SYSTEM_CALL,
 #ifdef CONFIG_ARM64_SVE
 	REGSET_SVE,
@@ -1495,6 +1529,14 @@ static const struct user_regset aarch64_regsets[] = {
 		.regset_get = system_call_get,
 		.set = system_call_set,
 	},
+	[REGSET_FPMR] = {
+		.core_note_type = NT_ARM_FPMR,
+		.n = 1,
+		.size = sizeof(u64),
+		.align = sizeof(u64),
+		.regset_get = fpmr_get,
+		.set = fpmr_set,
+	},
 #ifdef CONFIG_ARM64_SVE
 	[REGSET_SVE] = { /* Scalable Vector Extension */
 		.core_note_type = NT_ARM_SVE,
diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h
index 9417309b7230..b54b313bcf07 100644
--- a/include/uapi/linux/elf.h
+++ b/include/uapi/linux/elf.h
@@ -440,6 +440,7 @@ typedef struct elf64_shdr {
 #define NT_ARM_SSVE	0x40b		/* ARM Streaming SVE registers */
 #define NT_ARM_ZA	0x40c		/* ARM SME ZA registers */
 #define NT_ARM_ZT	0x40d		/* ARM SME ZT registers */
+#define NT_ARM_FPMR	0x40e		/* ARM floating point mode register */
 #define NT_ARC_V2	0x600		/* ARCv2 accumulator/extra registers */
 #define NT_VMCOREDD	0x700		/* Vmcore Device Dump Note */
 #define NT_MIPS_DSP	0x800		/* MIPS DSP ASE registers */

-- 
2.30.2


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[PATCH v3 14/21] KVM: arm64: Add newly allocated ID registers to register descriptions

[Mark Brown]

The 2023 architecture extensions have allocated some new ID registers, add
them to the KVM system register descriptions so that they are visible to
guests.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 4735e1b37fb3..b843da5e4bb9 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2139,12 +2139,12 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 		   ID_AA64PFR0_EL1_AdvSIMD |
 		   ID_AA64PFR0_EL1_FP), },
 	ID_SANITISED(ID_AA64PFR1_EL1),
-	ID_UNALLOCATED(4,2),
+	ID_SANITISED(ID_AA64PFR2_EL1),
 	ID_UNALLOCATED(4,3),
 	ID_WRITABLE(ID_AA64ZFR0_EL1, ~ID_AA64ZFR0_EL1_RES0),
 	ID_HIDDEN(ID_AA64SMFR0_EL1),
 	ID_UNALLOCATED(4,6),
-	ID_UNALLOCATED(4,7),
+	ID_SANITISED(ID_AA64FPFR0_EL1),
 
 	/* CRm=5 */
 	{ SYS_DESC(SYS_ID_AA64DFR0_EL1),
@@ -2171,7 +2171,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	ID_WRITABLE(ID_AA64ISAR2_EL1, ~(ID_AA64ISAR2_EL1_RES0 |
 					ID_AA64ISAR2_EL1_APA3 |
 					ID_AA64ISAR2_EL1_GPA3)),
-	ID_UNALLOCATED(6,3),
+	ID_WRITABLE(ID_AA64ISAR3_EL1, ~ID_AA64ISAR3_EL1_RES0),
 	ID_UNALLOCATED(6,4),
 	ID_UNALLOCATED(6,5),
 	ID_UNALLOCATED(6,6),

-- 
2.30.2


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[PATCH v3 15/21] KVM: arm64: Support FEAT_FPMR for guests

[Mark Brown]

FEAT_FPMR introduces a new system register FPMR which allows configuration
of floating point behaviour, currently for FP8 specific features. Allow use
of this in guests, disabling the trap while guests are running and saving
and restoring the value along with the rest of the floating point state.
Since FPMR is stored immediately after the main floating point state we
share it with the hypervisor by adjusting the size of the shared region.

Access to FPMR is covered by both a register specific trap HCRX_EL2.EnFPM
and the overall floating point access trap so we just unconditionally
enable the FPMR specific trap and rely on the floating point access trap to
detect guest floating point usage.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 arch/arm64/include/asm/kvm_arm.h        |  2 +-
 arch/arm64/include/asm/kvm_host.h       |  4 +++-
 arch/arm64/kvm/emulate-nested.c         |  9 +++++++++
 arch/arm64/kvm/fpsimd.c                 | 20 +++++++++++++++++---
 arch/arm64/kvm/hyp/include/hyp/switch.h |  7 ++++++-
 arch/arm64/kvm/sys_regs.c               | 11 +++++++++++
 6 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 9f9239d86900..95f3b44e7c3a 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -103,7 +103,7 @@
 #define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H)
 
 #define HCRX_GUEST_FLAGS \
-	(HCRX_EL2_SMPME | HCRX_EL2_TCR2En | \
+	(HCRX_EL2_SMPME | HCRX_EL2_TCR2En | HCRX_EL2_EnFPM | \
 	 (cpus_have_final_cap(ARM64_HAS_MOPS) ? (HCRX_EL2_MSCEn | HCRX_EL2_MCE2) : 0))
 #define HCRX_HOST_FLAGS (HCRX_EL2_MSCEn | HCRX_EL2_TCR2En | HCRX_EL2_EnFPM)
 
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index f8d98985a39c..9885adff06fa 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -391,6 +391,8 @@ enum vcpu_sysreg {
 	CNTP_CVAL_EL0,
 	CNTP_CTL_EL0,
 
+	FPMR,
+
 	/* Memory Tagging Extension registers */
 	RGSR_EL1,	/* Random Allocation Tag Seed Register */
 	GCR_EL1,	/* Tag Control Register */
@@ -517,7 +519,6 @@ struct kvm_vcpu_arch {
 	enum fp_type fp_type;
 	unsigned int sve_max_vl;
 	u64 svcr;
-	u64 fpmr;
 
 	/* Stage 2 paging state used by the hardware on next switch */
 	struct kvm_s2_mmu *hw_mmu;
@@ -576,6 +577,7 @@ struct kvm_vcpu_arch {
 	struct kvm_guest_debug_arch external_debug_state;
 
 	struct user_fpsimd_state *host_fpsimd_state;	/* hyp VA */
+	u64 *host_fpmr;					/* hyp VA */
 	struct task_struct *parent_task;
 
 	struct {
diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index 06185216a297..802e5cde696f 100644
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -67,6 +67,8 @@ enum cgt_group_id {
 	CGT_HCR_TTLBIS,
 	CGT_HCR_TTLBOS,
 
+	CGT_HCRX_EnFPM,
+
 	CGT_MDCR_TPMCR,
 	CGT_MDCR_TPM,
 	CGT_MDCR_TDE,
@@ -279,6 +281,12 @@ static const struct trap_bits coarse_trap_bits[] = {
 		.mask		= HCR_TTLBOS,
 		.behaviour	= BEHAVE_FORWARD_ANY,
 	},
+	[CGT_HCRX_EnFPM] = {
+		.index		= HCRX_EL2,
+		.value		= HCRX_EL2_EnFPM,
+		.mask		= HCRX_EL2_EnFPM,
+		.behaviour	= BEHAVE_FORWARD_ANY,
+	},
 	[CGT_MDCR_TPMCR] = {
 		.index		= MDCR_EL2,
 		.value		= MDCR_EL2_TPMCR,
@@ -478,6 +486,7 @@ static const struct encoding_to_trap_config encoding_to_cgt[] __initconst = {
 	SR_TRAP(SYS_AIDR_EL1,		CGT_HCR_TID1),
 	SR_TRAP(SYS_SMIDR_EL1,		CGT_HCR_TID1),
 	SR_TRAP(SYS_CTR_EL0,		CGT_HCR_TID2),
+	SR_TRAP(SYS_FPMR,		CGT_HCRX_EnFPM),
 	SR_TRAP(SYS_CCSIDR_EL1,		CGT_HCR_TID2_TID4),
 	SR_TRAP(SYS_CCSIDR2_EL1,	CGT_HCR_TID2_TID4),
 	SR_TRAP(SYS_CLIDR_EL1,		CGT_HCR_TID2_TID4),
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
index e3e611e30e91..dee078625d0d 100644
--- a/arch/arm64/kvm/fpsimd.c
+++ b/arch/arm64/kvm/fpsimd.c
@@ -14,6 +14,16 @@
 #include <asm/kvm_mmu.h>
 #include <asm/sysreg.h>
 
+static void *fpsimd_share_end(struct user_fpsimd_state *fpsimd)
+{
+	void *share_end = fpsimd + 1;
+
+	if (cpus_have_final_cap(ARM64_HAS_FPMR))
+		share_end += sizeof(u64);
+
+	return share_end;
+}
+
 void kvm_vcpu_unshare_task_fp(struct kvm_vcpu *vcpu)
 {
 	struct task_struct *p = vcpu->arch.parent_task;
@@ -23,7 +33,7 @@ void kvm_vcpu_unshare_task_fp(struct kvm_vcpu *vcpu)
 		return;
 
 	fpsimd = &p->thread.uw.fpsimd_state;
-	kvm_unshare_hyp(fpsimd, fpsimd + 1);
+	kvm_unshare_hyp(fpsimd, fpsimd_share_end(fpsimd));
 	put_task_struct(p);
 }
 
@@ -45,11 +55,15 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
 	kvm_vcpu_unshare_task_fp(vcpu);
 
 	/* Make sure the host task fpsimd state is visible to hyp: */
-	ret = kvm_share_hyp(fpsimd, fpsimd + 1);
+	ret = kvm_share_hyp(fpsimd, fpsimd_share_end(fpsimd));
 	if (ret)
 		return ret;
 
 	vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
+	if (cpus_have_final_cap(ARM64_HAS_FPMR)) {
+		WARN_ON_ONCE(&current->thread.fpmr + 1 != fpsimd_share_end(fpsimd));
+		vcpu->arch.host_fpmr = kern_hyp_va(&current->thread.fpmr);
+	}
 
 	/*
 	 * We need to keep current's task_struct pinned until its data has been
@@ -153,7 +167,7 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu)
 		fp_state.sve_vl = vcpu->arch.sve_max_vl;
 		fp_state.sme_state = NULL;
 		fp_state.svcr = &vcpu->arch.svcr;
-		fp_state.fpmr = &vcpu->arch.fpmr;
+		fp_state.fpmr = &__vcpu_sys_reg(vcpu, FPMR);
 		fp_state.fp_type = &vcpu->arch.fp_type;
 
 		if (vcpu_has_sve(vcpu))
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index f99d8af0b9af..a51b21a2e26f 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -339,10 +339,15 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
 	isb();
 
 	/* Write out the host state if it's in the registers */
-	if (vcpu->arch.fp_state == FP_STATE_HOST_OWNED)
+	if (vcpu->arch.fp_state == FP_STATE_HOST_OWNED) {
 		__fpsimd_save_state(vcpu->arch.host_fpsimd_state);
+		if (cpus_have_final_cap(ARM64_HAS_FPMR))
+			*vcpu->arch.host_fpmr = read_sysreg_s(SYS_FPMR);
+	}
 
 	/* Restore the guest state */
+	if (cpus_have_final_cap(ARM64_HAS_FPMR))
+		write_sysreg_s(__vcpu_sys_reg(vcpu, FPMR), SYS_FPMR);
 	if (sve_guest)
 		__hyp_sve_restore_guest(vcpu);
 	else
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index b843da5e4bb9..0789fb632623 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1914,6 +1914,15 @@ static unsigned int hidden_user_visibility(const struct kvm_vcpu *vcpu,
 	.visibility = hidden_user_visibility,	\
 }
 
+static unsigned int fpmr_visibility(const struct kvm_vcpu *vcpu,
+				    const struct sys_reg_desc *rd)
+{
+	if (cpus_have_final_cap(ARM64_HAS_FPMR))
+		return 0;
+
+	return REG_HIDDEN;
+}
+
 /*
  * Since reset() callback and field val are not used for idregs, they will be
  * used for specific purposes for idregs.
@@ -2310,6 +2319,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_CSSELR_EL1), access_csselr, reset_unknown, CSSELR_EL1 },
 	{ SYS_DESC(SYS_CTR_EL0), access_ctr },
 	{ SYS_DESC(SYS_SVCR), undef_access },
+	{ SYS_DESC(SYS_FPMR), access_rw, reset_unknown, FPMR,
+	  .visibility = fpmr_visibility },
 
 	{ PMU_SYS_REG(PMCR_EL0), .access = access_pmcr, .reset = reset_pmcr,
 	  .reg = PMCR_EL0, .get_user = get_pmcr, .set_user = set_pmcr },

-- 
2.30.2


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[PATCH v3 16/21] arm64/hwcap: Define hwcaps for 2023 DPISA features

[Mark Brown]

The 2023 architecture extensions include a large number of floating point
features, most of which simply add new instructions. Add hwcaps so that
userspace can enumerate these features.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 Documentation/arch/arm64/elf_hwcaps.rst | 49 +++++++++++++++++++++++++++++++++
 arch/arm64/include/asm/hwcap.h          | 15 ++++++++++
 arch/arm64/include/uapi/asm/hwcap.h     | 15 ++++++++++
 arch/arm64/kernel/cpufeature.c          | 35 +++++++++++++++++++++++
 arch/arm64/kernel/cpuinfo.c             | 15 ++++++++++
 5 files changed, 129 insertions(+)

diff --git a/Documentation/arch/arm64/elf_hwcaps.rst b/Documentation/arch/arm64/elf_hwcaps.rst
index ced7b335e2e0..448c1664879b 100644
--- a/Documentation/arch/arm64/elf_hwcaps.rst
+++ b/Documentation/arch/arm64/elf_hwcaps.rst
@@ -317,6 +317,55 @@ HWCAP2_LRCPC3
 HWCAP2_LSE128
     Functionality implied by ID_AA64ISAR0_EL1.Atomic == 0b0011.
 
+HWCAP2_FPMR
+    Functionality implied by ID_AA64PFR2_EL1.FMR == 0b0001.
+
+HWCAP2_LUT
+    Functionality implied by ID_AA64ISAR2_EL1.LUT == 0b0001.
+
+HWCAP2_FAMINMAX
+    Functionality implied by ID_AA64ISAR3_EL1.FAMINMAX == 0b0001.
+
+HWCAP2_F8CVT
+    Functionality implied by ID_AA64FPFR0_EL1.F8CVT == 0b1.
+
+HWCAP2_F8FMA
+    Functionality implied by ID_AA64FPFR0_EL1.F8FMA == 0b1.
+
+HWCAP2_F8DP4
+    Functionality implied by ID_AA64FPFR0_EL1.F8DP4 == 0b1.
+
+HWCAP2_F8DP2
+    Functionality implied by ID_AA64FPFR0_EL1.F8DP2 == 0b1.
+
+HWCAP2_F8E4M3
+    Functionality implied by ID_AA64FPFR0_EL1.F8E4M3 == 0b1.
+
+HWCAP2_F8E5M2
+    Functionality implied by ID_AA64FPFR0_EL1.F8E5M2 == 0b1.
+
+HWCAP2_SME_LUTV2
+    Functionality implied by ID_AA64SMFR0_EL1.LUTv2 == 0b1.
+
+HWCAP2_SME_F8F16
+    Functionality implied by ID_AA64SMFR0_EL1.F8F16 == 0b1.
+
+HWCAP2_SME_F8F32
+    Functionality implied by ID_AA64SMFR0_EL1.F8F32 == 0b1.
+
+HWCAP2_SME_SF8FMA
+    Functionality implied by ID_AA64SMFR0_EL1.SF8FMA == 0b1.
+
+HWCAP2_SME_SF8DP4
+    Functionality implied by ID_AA64SMFR0_EL1.SF8DP4 == 0b1.
+
+HWCAP2_SME_SF8DP2
+    Functionality implied by ID_AA64SMFR0_EL1.SF8DP2 == 0b1.
+
+HWCAP2_SME_SF8DP4
+    Functionality implied by ID_AA64SMFR0_EL1.SF8DP4 == 0b1.
+
+
 4. Unused AT_HWCAP bits
 -----------------------
 
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index cd71e09ea14d..4edd3b61df11 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -142,6 +142,21 @@
 #define KERNEL_HWCAP_SVE_B16B16		__khwcap2_feature(SVE_B16B16)
 #define KERNEL_HWCAP_LRCPC3		__khwcap2_feature(LRCPC3)
 #define KERNEL_HWCAP_LSE128		__khwcap2_feature(LSE128)
+#define KERNEL_HWCAP_FPMR		__khwcap2_feature(FPMR)
+#define KERNEL_HWCAP_LUT		__khwcap2_feature(LUT)
+#define KERNEL_HWCAP_FAMINMAX		__khwcap2_feature(FAMINMAX)
+#define KERNEL_HWCAP_F8CVT		__khwcap2_feature(F8CVT)
+#define KERNEL_HWCAP_F8FMA		__khwcap2_feature(F8FMA)
+#define KERNEL_HWCAP_F8DP4		__khwcap2_feature(F8DP4)
+#define KERNEL_HWCAP_F8DP2		__khwcap2_feature(F8DP2)
+#define KERNEL_HWCAP_F8E4M3		__khwcap2_feature(F8E4M3)
+#define KERNEL_HWCAP_F8E5M2		__khwcap2_feature(F8E5M2)
+#define KERNEL_HWCAP_SME_LUTV2		__khwcap2_feature(SME_LUTV2)
+#define KERNEL_HWCAP_SME_F8F16		__khwcap2_feature(SME_F8F16)
+#define KERNEL_HWCAP_SME_F8F32		__khwcap2_feature(SME_F8F32)
+#define KERNEL_HWCAP_SME_SF8FMA		__khwcap2_feature(SME_SF8FMA)
+#define KERNEL_HWCAP_SME_SF8DP4		__khwcap2_feature(SME_SF8DP4)
+#define KERNEL_HWCAP_SME_SF8DP2		__khwcap2_feature(SME_SF8DP2)
 
 /*
  * This yields a mask that user programs can use to figure out what
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index 5023599fa278..285610e626f5 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -107,5 +107,20 @@
 #define HWCAP2_SVE_B16B16	(1UL << 45)
 #define HWCAP2_LRCPC3		(1UL << 46)
 #define HWCAP2_LSE128		(1UL << 47)
+#define HWCAP2_FPMR		(1UL << 48)
+#define HWCAP2_LUT		(1UL << 49)
+#define HWCAP2_FAMINMAX		(1UL << 50)
+#define HWCAP2_F8CVT		(1UL << 51)
+#define HWCAP2_F8FMA		(1UL << 52)
+#define HWCAP2_F8DP4		(1UL << 53)
+#define HWCAP2_F8DP2		(1UL << 54)
+#define HWCAP2_F8E4M3		(1UL << 55)
+#define HWCAP2_F8E5M2		(1UL << 56)
+#define HWCAP2_SME_LUTV2	(1UL << 57)
+#define HWCAP2_SME_F8F16	(1UL << 58)
+#define HWCAP2_SME_F8F32	(1UL << 59)
+#define HWCAP2_SME_SF8FMA	(1UL << 60)
+#define HWCAP2_SME_SF8DP4	(1UL << 61)
+#define HWCAP2_SME_SF8DP2	(1UL << 62)
 
 #endif /* _UAPI__ASM_HWCAP_H */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index ea0b680792de..33e301b6e31e 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -220,6 +220,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar1[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64isar2[] = {
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_EL1_LUT_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_EL1_CSSC_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_EL1_RPRFM_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR2_EL1_CLRBHB_SHIFT, 4, 0),
@@ -235,6 +236,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar2[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64isar3[] = {
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64ISAR3_EL1_FAMINMAX_SHIFT, 4, 0),
 	ARM64_FTR_END,
 };
 
@@ -303,6 +305,8 @@ static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
 static const struct arm64_ftr_bits ftr_id_aa64smfr0[] = {
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_FA64_SHIFT, 1, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_LUTv2_SHIFT, 1, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SMEver_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
@@ -315,6 +319,10 @@ static const struct arm64_ftr_bits ftr_id_aa64smfr0[] = {
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_B16B16_SHIFT, 1, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_F16F16_SHIFT, 1, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_F8F16_SHIFT, 1, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_F8F32_SHIFT, 1, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_I8I32_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
@@ -325,10 +333,22 @@ static const struct arm64_ftr_bits ftr_id_aa64smfr0[] = {
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_BI32I32_SHIFT, 1, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
 		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_F32F32_SHIFT, 1, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SF8FMA_SHIFT, 1, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SF8DP4_SHIFT, 1, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME),
+		       FTR_STRICT, FTR_EXACT, ID_AA64SMFR0_EL1_SF8DP2_SHIFT, 1, 0),
 	ARM64_FTR_END,
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64fpfr0[] = {
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64FPFR0_EL1_F8CVT_SHIFT, 1, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64FPFR0_EL1_F8FMA_SHIFT, 1, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64FPFR0_EL1_F8DP4_SHIFT, 1, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64FPFR0_EL1_F8DP2_SHIFT, 1, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64FPFR0_EL1_F8E4M3_SHIFT, 1, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_EXACT, ID_AA64FPFR0_EL1_F8E5M2_SHIFT, 1, 0),
 	ARM64_FTR_END,
 };
 
@@ -2851,6 +2871,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
 	HWCAP_CAP(ID_AA64PFR0_EL1, AdvSIMD, IMP, CAP_HWCAP, KERNEL_HWCAP_ASIMD),
 	HWCAP_CAP(ID_AA64PFR0_EL1, AdvSIMD, FP16, CAP_HWCAP, KERNEL_HWCAP_ASIMDHP),
 	HWCAP_CAP(ID_AA64PFR0_EL1, DIT, IMP, CAP_HWCAP, KERNEL_HWCAP_DIT),
+	HWCAP_CAP(ID_AA64PFR2_EL1, FPMR, IMP, CAP_HWCAP, KERNEL_HWCAP_FPMR),
 	HWCAP_CAP(ID_AA64ISAR1_EL1, DPB, IMP, CAP_HWCAP, KERNEL_HWCAP_DCPOP),
 	HWCAP_CAP(ID_AA64ISAR1_EL1, DPB, DPB2, CAP_HWCAP, KERNEL_HWCAP_DCPODP),
 	HWCAP_CAP(ID_AA64ISAR1_EL1, JSCVT, IMP, CAP_HWCAP, KERNEL_HWCAP_JSCVT),
@@ -2864,6 +2885,8 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
 	HWCAP_CAP(ID_AA64ISAR1_EL1, BF16, EBF16, CAP_HWCAP, KERNEL_HWCAP_EBF16),
 	HWCAP_CAP(ID_AA64ISAR1_EL1, DGH, IMP, CAP_HWCAP, KERNEL_HWCAP_DGH),
 	HWCAP_CAP(ID_AA64ISAR1_EL1, I8MM, IMP, CAP_HWCAP, KERNEL_HWCAP_I8MM),
+	HWCAP_CAP(ID_AA64ISAR2_EL1, LUT, IMP, CAP_HWCAP, KERNEL_HWCAP_LUT),
+	HWCAP_CAP(ID_AA64ISAR3_EL1, FAMINMAX, IMP, CAP_HWCAP, KERNEL_HWCAP_FAMINMAX),
 	HWCAP_CAP(ID_AA64MMFR2_EL1, AT, IMP, CAP_HWCAP, KERNEL_HWCAP_USCAT),
 #ifdef CONFIG_ARM64_SVE
 	HWCAP_CAP(ID_AA64PFR0_EL1, SVE, IMP, CAP_HWCAP, KERNEL_HWCAP_SVE),
@@ -2904,6 +2927,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
 #ifdef CONFIG_ARM64_SME
 	HWCAP_CAP(ID_AA64PFR1_EL1, SME, IMP, CAP_HWCAP, KERNEL_HWCAP_SME),
 	HWCAP_CAP(ID_AA64SMFR0_EL1, FA64, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_FA64),
+	HWCAP_CAP(ID_AA64SMFR0_EL1, LUTv2, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_LUTV2),
 	HWCAP_CAP(ID_AA64SMFR0_EL1, SMEver, SME2p1, CAP_HWCAP, KERNEL_HWCAP_SME2P1),
 	HWCAP_CAP(ID_AA64SMFR0_EL1, SMEver, SME2, CAP_HWCAP, KERNEL_HWCAP_SME2),
 	HWCAP_CAP(ID_AA64SMFR0_EL1, I16I64, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_I16I64),
@@ -2911,12 +2935,23 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
 	HWCAP_CAP(ID_AA64SMFR0_EL1, I16I32, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_I16I32),
 	HWCAP_CAP(ID_AA64SMFR0_EL1, B16B16, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_B16B16),
 	HWCAP_CAP(ID_AA64SMFR0_EL1, F16F16, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_F16F16),
+	HWCAP_CAP(ID_AA64SMFR0_EL1, F8F16, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_F8F16),
+	HWCAP_CAP(ID_AA64SMFR0_EL1, F8F32, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_F8F32),
 	HWCAP_CAP(ID_AA64SMFR0_EL1, I8I32, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_I8I32),
 	HWCAP_CAP(ID_AA64SMFR0_EL1, F16F32, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_F16F32),
 	HWCAP_CAP(ID_AA64SMFR0_EL1, B16F32, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_B16F32),
 	HWCAP_CAP(ID_AA64SMFR0_EL1, BI32I32, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_BI32I32),
 	HWCAP_CAP(ID_AA64SMFR0_EL1, F32F32, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_F32F32),
+	HWCAP_CAP(ID_AA64SMFR0_EL1, SF8FMA, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_SF8FMA),
+	HWCAP_CAP(ID_AA64SMFR0_EL1, SF8DP4, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_SF8DP4),
+	HWCAP_CAP(ID_AA64SMFR0_EL1, SF8DP2, IMP, CAP_HWCAP, KERNEL_HWCAP_SME_SF8DP2),
 #endif /* CONFIG_ARM64_SME */
+	HWCAP_CAP(ID_AA64FPFR0_EL1, F8CVT, IMP, CAP_HWCAP, KERNEL_HWCAP_F8CVT),
+	HWCAP_CAP(ID_AA64FPFR0_EL1, F8FMA, IMP, CAP_HWCAP, KERNEL_HWCAP_F8FMA),
+	HWCAP_CAP(ID_AA64FPFR0_EL1, F8DP4, IMP, CAP_HWCAP, KERNEL_HWCAP_F8DP4),
+	HWCAP_CAP(ID_AA64FPFR0_EL1, F8DP2, IMP, CAP_HWCAP, KERNEL_HWCAP_F8DP2),
+	HWCAP_CAP(ID_AA64FPFR0_EL1, F8E4M3, IMP, CAP_HWCAP, KERNEL_HWCAP_F8E4M3),
+	HWCAP_CAP(ID_AA64FPFR0_EL1, F8E5M2, IMP, CAP_HWCAP, KERNEL_HWCAP_F8E5M2),
 	{},
 };
 
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 8322e968fd0d..29155107d35d 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -130,6 +130,21 @@ static const char *const hwcap_str[] = {
 	[KERNEL_HWCAP_SVE_B16B16]	= "sveb16b16",
 	[KERNEL_HWCAP_LRCPC3]		= "lrcpc3",
 	[KERNEL_HWCAP_LSE128]		= "lse128",
+	[KERNEL_HWCAP_FPMR]		= "fpmr",
+	[KERNEL_HWCAP_LUT]		= "lut",
+	[KERNEL_HWCAP_FAMINMAX]		= "faminmax",
+	[KERNEL_HWCAP_F8CVT]		= "f8cvt",
+	[KERNEL_HWCAP_F8FMA]		= "f8fma",
+	[KERNEL_HWCAP_F8DP4]		= "f8dp4",
+	[KERNEL_HWCAP_F8DP2]		= "f8dp2",
+	[KERNEL_HWCAP_F8E4M3]		= "f8e4m3",
+	[KERNEL_HWCAP_F8E5M2]		= "f8e5m2",
+	[KERNEL_HWCAP_SME_LUTV2]	= "smelutv2",
+	[KERNEL_HWCAP_SME_F8F16]	= "smef8f16",
+	[KERNEL_HWCAP_SME_F8F32]	= "smef8f32",
+	[KERNEL_HWCAP_SME_SF8FMA]	= "smesf8fma",
+	[KERNEL_HWCAP_SME_SF8DP4]	= "smesf8dp4",
+	[KERNEL_HWCAP_SME_SF8DP2]	= "smesf8dp2",
 };
 
 #ifdef CONFIG_COMPAT

-- 
2.30.2


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[PATCH v3 17/21] kselftest/arm64: Handle FPMR context in generic signal frame parser

[Mark Brown]

Teach the generic signal frame parsing code about the newly added FPMR
frame, avoiding warnings every time one is generated.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/arm64/signal/testcases/testcases.c | 8 ++++++++
 tools/testing/selftests/arm64/signal/testcases/testcases.h | 1 +
 2 files changed, 9 insertions(+)

diff --git a/tools/testing/selftests/arm64/signal/testcases/testcases.c b/tools/testing/selftests/arm64/signal/testcases/testcases.c
index 9f580b55b388..674b88cc8c39 100644
--- a/tools/testing/selftests/arm64/signal/testcases/testcases.c
+++ b/tools/testing/selftests/arm64/signal/testcases/testcases.c
@@ -209,6 +209,14 @@ bool validate_reserved(ucontext_t *uc, size_t resv_sz, char **err)
 			zt = (struct zt_context *)head;
 			new_flags |= ZT_CTX;
 			break;
+		case FPMR_MAGIC:
+			if (flags & FPMR_CTX)
+				*err = "Multiple FPMR_MAGIC";
+			else if (head->size !=
+				 sizeof(struct fpmr_context))
+				*err = "Bad size for fpmr_context";
+			new_flags |= FPMR_CTX;
+			break;
 		case EXTRA_MAGIC:
 			if (flags & EXTRA_CTX)
 				*err = "Multiple EXTRA_MAGIC";
diff --git a/tools/testing/selftests/arm64/signal/testcases/testcases.h b/tools/testing/selftests/arm64/signal/testcases/testcases.h
index a08ab0d6207a..7727126347e0 100644
--- a/tools/testing/selftests/arm64/signal/testcases/testcases.h
+++ b/tools/testing/selftests/arm64/signal/testcases/testcases.h
@@ -19,6 +19,7 @@
 #define ZA_CTX		(1 << 2)
 #define EXTRA_CTX	(1 << 3)
 #define ZT_CTX		(1 << 4)
+#define FPMR_CTX	(1 << 5)
 
 #define KSFT_BAD_MAGIC	0xdeadbeef
 

-- 
2.30.2


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[PATCH v3 18/21] kselftest/arm64: Add basic FPMR test

[Mark Brown]

Verify that a FPMR frame is generated on systems that support FPMR and not
generated otherwise.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/arm64/signal/.gitignore    |  1 +
 .../arm64/signal/testcases/fpmr_siginfo.c          | 82 ++++++++++++++++++++++
 2 files changed, 83 insertions(+)

diff --git a/tools/testing/selftests/arm64/signal/.gitignore b/tools/testing/selftests/arm64/signal/.gitignore
index 839e3a252629..1ce5b5eac386 100644
--- a/tools/testing/selftests/arm64/signal/.gitignore
+++ b/tools/testing/selftests/arm64/signal/.gitignore
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 mangle_*
 fake_sigreturn_*
+fpmr_*
 sme_*
 ssve_*
 sve_*
diff --git a/tools/testing/selftests/arm64/signal/testcases/fpmr_siginfo.c b/tools/testing/selftests/arm64/signal/testcases/fpmr_siginfo.c
new file mode 100644
index 000000000000..e9d24685e741
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fpmr_siginfo.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023 ARM Limited
+ *
+ * Verify that the FPMR register context in signal frames is set up as
+ * expected.
+ */
+
+#include <signal.h>
+#include <ucontext.h>
+#include <sys/auxv.h>
+#include <sys/prctl.h>
+#include <unistd.h>
+#include <asm/sigcontext.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+static union {
+	ucontext_t uc;
+	char buf[1024 * 128];
+} context;
+
+#define SYS_FPMR "S3_3_C4_C4_2"
+
+static uint64_t get_fpmr(void)
+{
+	uint64_t val;
+
+	asm volatile (
+		"mrs	%0, " SYS_FPMR "\n"
+		: "=r"(val)
+		:
+		: "cc");
+
+	return val;
+}
+
+int fpmr_present(struct tdescr *td, siginfo_t *si, ucontext_t *uc)
+{
+	struct _aarch64_ctx *head = GET_BUF_RESV_HEAD(context);
+	struct fpmr_context *fpmr_ctx;
+	size_t offset;
+	bool in_sigframe;
+	bool have_fpmr;
+	__u64 orig_fpmr;
+
+	have_fpmr = getauxval(AT_HWCAP2) & HWCAP2_FPMR;
+	if (have_fpmr)
+		orig_fpmr = get_fpmr();
+
+	if (!get_current_context(td, &context.uc, sizeof(context)))
+		return 1;
+
+	fpmr_ctx = (struct fpmr_context *)
+		get_header(head, FPMR_MAGIC, td->live_sz, &offset);
+
+	in_sigframe = fpmr_ctx != NULL;
+
+	fprintf(stderr, "FPMR sigframe %s on system %s FPMR\n",
+		in_sigframe ? "present" : "absent",
+		have_fpmr ? "with" : "without");
+
+	td->pass = (in_sigframe == have_fpmr);
+
+	if (have_fpmr && fpmr_ctx) {
+		if (fpmr_ctx->fpmr != orig_fpmr) {
+			fprintf(stderr, "FPMR in frame is %llx, was %llx\n",
+				fpmr_ctx->fpmr, orig_fpmr);
+			td->pass = false;
+		}
+	}
+
+	return 0;
+}
+
+struct tdescr tde = {
+	.name = "FPMR",
+	.descr = "Validate that FPMR is present as expected",
+	.timeout = 3,
+	.run = fpmr_present,
+};

-- 
2.30.2


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[PATCH v3 19/21] kselftest/arm64: Add 2023 DPISA hwcap test coverage

[Mark Brown]

Add the hwcaps added for the 2023 DPISA extensions to the hwcaps test
program.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/arm64/abi/hwcap.c | 217 ++++++++++++++++++++++++++++++
 1 file changed, 217 insertions(+)

diff --git a/tools/testing/selftests/arm64/abi/hwcap.c b/tools/testing/selftests/arm64/abi/hwcap.c
index 1189e77c8152..d8909b2b535a 100644
--- a/tools/testing/selftests/arm64/abi/hwcap.c
+++ b/tools/testing/selftests/arm64/abi/hwcap.c
@@ -58,11 +58,46 @@ static void cssc_sigill(void)
 	asm volatile(".inst 0xdac01c00" : : : "x0");
 }
 
+static void f8cvt_sigill(void)
+{
+	/* FSCALE V0.4H, V0.4H, V0.4H */
+	asm volatile(".inst 0x2ec03c00");
+}
+
+static void f8dp2_sigill(void)
+{
+	/* FDOT V0.4H, V0.4H, V0.5H */
+	asm volatile(".inst 0xe40fc00");
+}
+
+static void f8dp4_sigill(void)
+{
+	/* FDOT V0.2S, V0.2S, V0.2S */
+	asm volatile(".inst 0xe00fc00");
+}
+
+static void f8fma_sigill(void)
+{
+	/* FMLALB V0.8H, V0.16B, V0.16B */
+	asm volatile(".inst 0xec0fc00");
+}
+
+static void faminmax_sigill(void)
+{
+	/* FAMIN V0.4H, V0.4H, V0.4H */
+	asm volatile(".inst 0x2ec01c00");
+}
+
 static void fp_sigill(void)
 {
 	asm volatile("fmov s0, #1");
 }
 
+static void fpmr_sigill(void)
+{
+	asm volatile("mrs x0, S3_3_C4_C4_2" : : : "x0");
+}
+
 static void ilrcpc_sigill(void)
 {
 	/* LDAPUR W0, [SP, #8] */
@@ -95,6 +130,12 @@ static void lse128_sigill(void)
 		     : "cc", "memory");
 }
 
+static void lut_sigill(void)
+{
+	/* LUTI2 V0.16B, { V0.16B }, V[0] */
+	asm volatile(".inst 0x4e801000");
+}
+
 static void mops_sigill(void)
 {
 	char dst[1], src[1];
@@ -216,6 +257,78 @@ static void smef16f16_sigill(void)
 	asm volatile("msr S0_3_C4_C6_3, xzr" : : : );
 }
 
+static void smef8f16_sigill(void)
+{
+	/* SMSTART */
+	asm volatile("msr S0_3_C4_C7_3, xzr" : : : );
+
+	/* FDOT ZA.H[W0, 0], Z0.B-Z1.B, Z0.B-Z1.B */
+	asm volatile(".inst 0xc1a01020" : : : );
+
+	/* SMSTOP */
+	asm volatile("msr S0_3_C4_C6_3, xzr" : : : );
+}
+
+static void smef8f32_sigill(void)
+{
+	/* SMSTART */
+	asm volatile("msr S0_3_C4_C7_3, xzr" : : : );
+
+	/* FDOT ZA.S[W0, 0], { Z0.B-Z1.B }, Z0.B[0] */
+	asm volatile(".inst 0xc1500038" : : : );
+
+	/* SMSTOP */
+	asm volatile("msr S0_3_C4_C6_3, xzr" : : : );
+}
+
+static void smelutv2_sigill(void)
+{
+	/* SMSTART */
+	asm volatile("msr S0_3_C4_C7_3, xzr" : : : );
+
+	/* LUTI4 { Z0.B-Z3.B }, ZT0, { Z0-Z1 } */
+	asm volatile(".inst 0xc08b0000" : : : );
+
+	/* SMSTOP */
+	asm volatile("msr S0_3_C4_C6_3, xzr" : : : );
+}
+
+static void smesf8dp2_sigill(void)
+{
+	/* SMSTART */
+	asm volatile("msr S0_3_C4_C7_3, xzr" : : : );
+
+	/* FDOT Z0.H, Z0.B, Z0.B[0] */
+	asm volatile(".inst 0x64204400" : : : );
+
+	/* SMSTOP */
+	asm volatile("msr S0_3_C4_C6_3, xzr" : : : );
+}
+
+static void smesf8dp4_sigill(void)
+{
+	/* SMSTART */
+	asm volatile("msr S0_3_C4_C7_3, xzr" : : : );
+
+	/* FDOT Z0.S, Z0.B, Z0.B[0] */
+	asm volatile(".inst 0xc1a41C00" : : : );
+
+	/* SMSTOP */
+	asm volatile("msr S0_3_C4_C6_3, xzr" : : : );
+}
+
+static void smesf8fma_sigill(void)
+{
+	/* SMSTART */
+	asm volatile("msr S0_3_C4_C7_3, xzr" : : : );
+
+	/* FMLALB V0.8H, V0.16B, V0.16B */
+	asm volatile(".inst 0xec0fc00");
+
+	/* SMSTOP */
+	asm volatile("msr S0_3_C4_C6_3, xzr" : : : );
+}
+
 static void sve_sigill(void)
 {
 	/* RDVL x0, #0 */
@@ -353,6 +466,53 @@ static const struct hwcap_data {
 		.cpuinfo = "cssc",
 		.sigill_fn = cssc_sigill,
 	},
+	{
+		.name = "F8CVT",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_F8CVT,
+		.cpuinfo = "f8cvt",
+		.sigill_fn = f8cvt_sigill,
+	},
+	{
+		.name = "F8DP4",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_F8DP4,
+		.cpuinfo = "f8dp4",
+		.sigill_fn = f8dp4_sigill,
+	},
+	{
+		.name = "F8DP2",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_F8DP2,
+		.cpuinfo = "f8dp4",
+		.sigill_fn = f8dp2_sigill,
+	},
+	{
+		.name = "F8E5M2",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_F8E5M2,
+		.cpuinfo = "f8e5m2",
+	},
+	{
+		.name = "F8E4M3",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_F8E4M3,
+		.cpuinfo = "f8e4m3",
+	},
+	{
+		.name = "F8FMA",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_F8FMA,
+		.cpuinfo = "f8fma",
+		.sigill_fn = f8fma_sigill,
+	},
+	{
+		.name = "FAMINMAX",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_FAMINMAX,
+		.cpuinfo = "faminmax",
+		.sigill_fn = faminmax_sigill,
+	},
 	{
 		.name = "FP",
 		.at_hwcap = AT_HWCAP,
@@ -360,6 +520,14 @@ static const struct hwcap_data {
 		.cpuinfo = "fp",
 		.sigill_fn = fp_sigill,
 	},
+	{
+		.name = "FPMR",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_FPMR,
+		.cpuinfo = "fpmr",
+		.sigill_fn = fpmr_sigill,
+		.sigill_reliable = true,
+	},
 	{
 		.name = "JSCVT",
 		.at_hwcap = AT_HWCAP,
@@ -411,6 +579,13 @@ static const struct hwcap_data {
 		.cpuinfo = "lse128",
 		.sigill_fn = lse128_sigill,
 	},
+	{
+		.name = "LUT",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_LUT,
+		.cpuinfo = "lut",
+		.sigill_fn = lut_sigill,
+	},
 	{
 		.name = "MOPS",
 		.at_hwcap = AT_HWCAP2,
@@ -511,6 +686,48 @@ static const struct hwcap_data {
 		.cpuinfo = "smef16f16",
 		.sigill_fn = smef16f16_sigill,
 	},
+	{
+		.name = "SME F8F16",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_SME_F8F16,
+		.cpuinfo = "smef8f16",
+		.sigill_fn = smef8f16_sigill,
+	},
+	{
+		.name = "SME F8F32",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_SME_F8F32,
+		.cpuinfo = "smef8f32",
+		.sigill_fn = smef8f32_sigill,
+	},
+	{
+		.name = "SME LUTV2",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_SME_LUTV2,
+		.cpuinfo = "smelutv2",
+		.sigill_fn = smelutv2_sigill,
+	},
+	{
+		.name = "SME SF8FMA",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_SME_SF8FMA,
+		.cpuinfo = "smesf8fma",
+		.sigill_fn = smesf8fma_sigill,
+	},
+	{
+		.name = "SME SF8DP2",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_SME_SF8DP2,
+		.cpuinfo = "smesf8dp2",
+		.sigill_fn = smesf8dp2_sigill,
+	},
+	{
+		.name = "SME SF8DP4",
+		.at_hwcap = AT_HWCAP2,
+		.hwcap_bit = HWCAP2_SME_SF8DP4,
+		.cpuinfo = "smesf8dp4",
+		.sigill_fn = smesf8dp4_sigill,
+	},
 	{
 		.name = "SVE",
 		.at_hwcap = AT_HWCAP,

-- 
2.30.2


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[PATCH v3 20/21] KVM: arm64: selftests: Document feature registers added in 2023 extensions

[Mark Brown]

The 2023 architecture extensions allocated some previously usused feature
registers, add comments mapping the names in get-reg-list as we do for the
other allocated registers.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/kvm/aarch64/get-reg-list.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/aarch64/get-reg-list.c b/tools/testing/selftests/kvm/aarch64/get-reg-list.c
index 709d7d721760..71ea6ecec7ce 100644
--- a/tools/testing/selftests/kvm/aarch64/get-reg-list.c
+++ b/tools/testing/selftests/kvm/aarch64/get-reg-list.c
@@ -428,7 +428,7 @@ static __u64 base_regs[] = {
 	ARM64_SYS_REG(3, 0, 0, 4, 4),	/* ID_AA64ZFR0_EL1 */
 	ARM64_SYS_REG(3, 0, 0, 4, 5),	/* ID_AA64SMFR0_EL1 */
 	ARM64_SYS_REG(3, 0, 0, 4, 6),
-	ARM64_SYS_REG(3, 0, 0, 4, 7),
+	ARM64_SYS_REG(3, 0, 0, 4, 7),	/* ID_AA64FPFR_EL1 */
 	ARM64_SYS_REG(3, 0, 0, 5, 0),	/* ID_AA64DFR0_EL1 */
 	ARM64_SYS_REG(3, 0, 0, 5, 1),	/* ID_AA64DFR1_EL1 */
 	ARM64_SYS_REG(3, 0, 0, 5, 2),
@@ -440,7 +440,7 @@ static __u64 base_regs[] = {
 	ARM64_SYS_REG(3, 0, 0, 6, 0),	/* ID_AA64ISAR0_EL1 */
 	ARM64_SYS_REG(3, 0, 0, 6, 1),	/* ID_AA64ISAR1_EL1 */
 	ARM64_SYS_REG(3, 0, 0, 6, 2),	/* ID_AA64ISAR2_EL1 */
-	ARM64_SYS_REG(3, 0, 0, 6, 3),
+	ARM64_SYS_REG(3, 0, 0, 6, 3),	/* ID_AA64ISAR3_EL1 */
 	ARM64_SYS_REG(3, 0, 0, 6, 4),
 	ARM64_SYS_REG(3, 0, 0, 6, 5),
 	ARM64_SYS_REG(3, 0, 0, 6, 6),

-- 
2.30.2


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[PATCH v3 21/21] KVM: arm64: selftests: Teach get-reg-list about FPMR

[Mark Brown]

FEAT_FPMR defines a new register FMPR which is available at all ELs and is
discovered via ID_AA64PFR2_EL1.FPMR, add this to the set of registers that
get-reg-list knows to check for with the required identification register
depdendency.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/kvm/aarch64/get-reg-list.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/testing/selftests/kvm/aarch64/get-reg-list.c b/tools/testing/selftests/kvm/aarch64/get-reg-list.c
index 71ea6ecec7ce..1e43511d1440 100644
--- a/tools/testing/selftests/kvm/aarch64/get-reg-list.c
+++ b/tools/testing/selftests/kvm/aarch64/get-reg-list.c
@@ -40,6 +40,12 @@ static struct feature_id_reg feat_id_regs[] = {
 		ARM64_SYS_REG(3, 0, 0, 7, 3),	/* ID_AA64MMFR3_EL1 */
 		4,
 		1
+	},
+	{
+		ARM64_SYS_REG(3, 3, 4, 4, 2),	/* FPMR */
+		ARM64_SYS_REG(3, 0, 0, 4, 2),	/* ID_AA64PFR2_EL1 */
+		32,
+		1
 	}
 };
 
@@ -481,6 +487,7 @@ static __u64 base_regs[] = {
 	ARM64_SYS_REG(3, 3, 14, 2, 1),	/* CNTP_CTL_EL0 */
 	ARM64_SYS_REG(3, 3, 14, 2, 2),	/* CNTP_CVAL_EL0 */
 	ARM64_SYS_REG(3, 4, 3, 0, 0),	/* DACR32_EL2 */
+	ARM64_SYS_REG(3, 3, 4, 4, 2),	/* FPMR */
 	ARM64_SYS_REG(3, 4, 5, 0, 1),	/* IFSR32_EL2 */
 	ARM64_SYS_REG(3, 4, 5, 3, 0),	/* FPEXC32_EL2 */
 };

-- 
2.30.2


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Re: [PATCH v3 15/21] KVM: arm64: Support FEAT_FPMR for guests

[Marc Zyngier]

On Tue, 05 Dec 2023 16:48:13 +0000,
Mark Brown <broonie@kernel.org> wrote:
> 
> FEAT_FPMR introduces a new system register FPMR which allows configuration
> of floating point behaviour, currently for FP8 specific features. Allow use
> of this in guests, disabling the trap while guests are running and saving
> and restoring the value along with the rest of the floating point state.
> Since FPMR is stored immediately after the main floating point state we
> share it with the hypervisor by adjusting the size of the shared region.
> 
> Access to FPMR is covered by both a register specific trap HCRX_EL2.EnFPM
> and the overall floating point access trap so we just unconditionally
> enable the FPMR specific trap and rely on the floating point access trap to
> detect guest floating point usage.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>  arch/arm64/include/asm/kvm_arm.h        |  2 +-
>  arch/arm64/include/asm/kvm_host.h       |  4 +++-
>  arch/arm64/kvm/emulate-nested.c         |  9 +++++++++
>  arch/arm64/kvm/fpsimd.c                 | 20 +++++++++++++++++---
>  arch/arm64/kvm/hyp/include/hyp/switch.h |  7 ++++++-
>  arch/arm64/kvm/sys_regs.c               | 11 +++++++++++
>  6 files changed, 47 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
> index 9f9239d86900..95f3b44e7c3a 100644
> --- a/arch/arm64/include/asm/kvm_arm.h
> +++ b/arch/arm64/include/asm/kvm_arm.h
> @@ -103,7 +103,7 @@
>  #define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H)
>  
>  #define HCRX_GUEST_FLAGS \
> -	(HCRX_EL2_SMPME | HCRX_EL2_TCR2En | \
> +	(HCRX_EL2_SMPME | HCRX_EL2_TCR2En | HCRX_EL2_EnFPM | \

We really should start making all of these things conditional. See
below.

>  	 (cpus_have_final_cap(ARM64_HAS_MOPS) ? (HCRX_EL2_MSCEn | HCRX_EL2_MCE2) : 0))
>  #define HCRX_HOST_FLAGS (HCRX_EL2_MSCEn | HCRX_EL2_TCR2En | HCRX_EL2_EnFPM)
>  
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index f8d98985a39c..9885adff06fa 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -391,6 +391,8 @@ enum vcpu_sysreg {
>  	CNTP_CVAL_EL0,
>  	CNTP_CTL_EL0,
>  
> +	FPMR,
> +
>  	/* Memory Tagging Extension registers */
>  	RGSR_EL1,	/* Random Allocation Tag Seed Register */
>  	GCR_EL1,	/* Tag Control Register */
> @@ -517,7 +519,6 @@ struct kvm_vcpu_arch {
>  	enum fp_type fp_type;
>  	unsigned int sve_max_vl;
>  	u64 svcr;
> -	u64 fpmr;

Why do this change here? Why isn't done like that the first place?

>  
>  	/* Stage 2 paging state used by the hardware on next switch */
>  	struct kvm_s2_mmu *hw_mmu;
> @@ -576,6 +577,7 @@ struct kvm_vcpu_arch {
>  	struct kvm_guest_debug_arch external_debug_state;
>  
>  	struct user_fpsimd_state *host_fpsimd_state;	/* hyp VA */
> +	u64 *host_fpmr;					/* hyp VA */
>  	struct task_struct *parent_task;
>  
>  	struct {
> diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
> index 06185216a297..802e5cde696f 100644
> --- a/arch/arm64/kvm/emulate-nested.c
> +++ b/arch/arm64/kvm/emulate-nested.c
> @@ -67,6 +67,8 @@ enum cgt_group_id {
>  	CGT_HCR_TTLBIS,
>  	CGT_HCR_TTLBOS,
>  
> +	CGT_HCRX_EnFPM,
> +
>  	CGT_MDCR_TPMCR,
>  	CGT_MDCR_TPM,
>  	CGT_MDCR_TDE,
> @@ -279,6 +281,12 @@ static const struct trap_bits coarse_trap_bits[] = {
>  		.mask		= HCR_TTLBOS,
>  		.behaviour	= BEHAVE_FORWARD_ANY,
>  	},
> +	[CGT_HCRX_EnFPM] = {
> +		.index		= HCRX_EL2,
> +		.value		= HCRX_EL2_EnFPM,
> +		.mask		= HCRX_EL2_EnFPM,
> +		.behaviour	= BEHAVE_FORWARD_ANY,

This looks wrong. HCRX_EL2.EnFPM is an enable bit.

> +	},
>  	[CGT_MDCR_TPMCR] = {
>  		.index		= MDCR_EL2,
>  		.value		= MDCR_EL2_TPMCR,
> @@ -478,6 +486,7 @@ static const struct encoding_to_trap_config encoding_to_cgt[] __initconst = {
>  	SR_TRAP(SYS_AIDR_EL1,		CGT_HCR_TID1),
>  	SR_TRAP(SYS_SMIDR_EL1,		CGT_HCR_TID1),
>  	SR_TRAP(SYS_CTR_EL0,		CGT_HCR_TID2),
> +	SR_TRAP(SYS_FPMR,		CGT_HCRX_EnFPM),
>  	SR_TRAP(SYS_CCSIDR_EL1,		CGT_HCR_TID2_TID4),
>  	SR_TRAP(SYS_CCSIDR2_EL1,	CGT_HCR_TID2_TID4),
>  	SR_TRAP(SYS_CLIDR_EL1,		CGT_HCR_TID2_TID4),
> diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
> index e3e611e30e91..dee078625d0d 100644
> --- a/arch/arm64/kvm/fpsimd.c
> +++ b/arch/arm64/kvm/fpsimd.c
> @@ -14,6 +14,16 @@
>  #include <asm/kvm_mmu.h>
>  #include <asm/sysreg.h>
>  
> +static void *fpsimd_share_end(struct user_fpsimd_state *fpsimd)
> +{
> +	void *share_end = fpsimd + 1;
> +
> +	if (cpus_have_final_cap(ARM64_HAS_FPMR))
> +		share_end += sizeof(u64);
> +
> +	return share_end;
> +}

This is horrible. Why can't you just have a new structure wrapping
both user_fpsimd_state and fpmr? This is going to break in subtle
ways, just like the SVE/SME stuff.

> +
>  void kvm_vcpu_unshare_task_fp(struct kvm_vcpu *vcpu)
>  {
>  	struct task_struct *p = vcpu->arch.parent_task;
> @@ -23,7 +33,7 @@ void kvm_vcpu_unshare_task_fp(struct kvm_vcpu *vcpu)
>  		return;
>  
>  	fpsimd = &p->thread.uw.fpsimd_state;
> -	kvm_unshare_hyp(fpsimd, fpsimd + 1);
> +	kvm_unshare_hyp(fpsimd, fpsimd_share_end(fpsimd));
>  	put_task_struct(p);
>  }
>  
> @@ -45,11 +55,15 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
>  	kvm_vcpu_unshare_task_fp(vcpu);
>  
>  	/* Make sure the host task fpsimd state is visible to hyp: */
> -	ret = kvm_share_hyp(fpsimd, fpsimd + 1);
> +	ret = kvm_share_hyp(fpsimd, fpsimd_share_end(fpsimd));
>  	if (ret)
>  		return ret;
>  
>  	vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
> +	if (cpus_have_final_cap(ARM64_HAS_FPMR)) {
> +		WARN_ON_ONCE(&current->thread.fpmr + 1 != fpsimd_share_end(fpsimd));

How can this happen?

> +		vcpu->arch.host_fpmr = kern_hyp_va(&current->thread.fpmr);
> +	}

We really need to stop piling the save/restore of stuff that isn't
advertised to the guest.

	M.

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Re: [PATCH v3 15/21] KVM: arm64: Support FEAT_FPMR for guests

[Mark Brown]

[-- Attachment #1.1: Type: text/plain, Size: 3382 bytes --]

On Thu, Dec 07, 2023 at 08:39:46AM +0000, Marc Zyngier wrote:
> Mark Brown <broonie@kernel.org> wrote:

> >  #define HCRX_GUEST_FLAGS \
> > -	(HCRX_EL2_SMPME | HCRX_EL2_TCR2En | \
> > +	(HCRX_EL2_SMPME | HCRX_EL2_TCR2En | HCRX_EL2_EnFPM | \

> We really should start making all of these things conditional. See
> below.

Is there an overarching theory behind how these things are intended to
work?  I agree with you that I'd have expected more conditionality here,
I was trying to fit in with the existing pattern.  It's kind of hard to
follow what the intention is, I think to some extent due to things
having evolved over time.

> > @@ -517,7 +519,6 @@ struct kvm_vcpu_arch {
> >  	enum fp_type fp_type;
> >  	unsigned int sve_max_vl;
> >  	u64 svcr;
> > -	u64 fpmr;

> Why do this change here? Why isn't done like that the first place?

It didn't seem right to add the register to struct vcpu_sysreg before it
was handled by KVM.  As referenced in the cover letter normally this
wouldn't come up because KVM doesn't rely on the host kernel for
managing register state so we add KVM support then enable the host
kernel but for FPSIMD we're reusing fpsimd_save() so we need the host
kernel support to be in place when we enable KVM.

> >  	CGT_MDCR_TDE,
> > @@ -279,6 +281,12 @@ static const struct trap_bits coarse_trap_bits[] = {
> >  		.mask		= HCR_TTLBOS,
> >  		.behaviour	= BEHAVE_FORWARD_ANY,
> >  	},
> > +	[CGT_HCRX_EnFPM] = {
> > +		.index		= HCRX_EL2,
> > +		.value		= HCRX_EL2_EnFPM,
> > +		.mask		= HCRX_EL2_EnFPM,
> > +		.behaviour	= BEHAVE_FORWARD_ANY,

> This looks wrong. HCRX_EL2.EnFPM is an enable bit.

Right, it's the wrong way round.

> > +static void *fpsimd_share_end(struct user_fpsimd_state *fpsimd)
> > +{
> > +	void *share_end = fpsimd + 1;
> > +
> > +	if (cpus_have_final_cap(ARM64_HAS_FPMR))
> > +		share_end += sizeof(u64);
> > +
> > +	return share_end;
> > +}

> This is horrible. Why can't you just have a new structure wrapping
> both user_fpsimd_state and fpmr? This is going to break in subtle
> ways, just like the SVE/SME stuff.

I agree that it's not great, the main issue was that fpsimd_state is
both already embedded in uw for hardened usercopy and very widely
referenced by exactly which struct it's in so I was taking a guess as to
what would get the least objections.  The obvious thing would be to add
FPMR to uw and share the whole thing with the hypervisor, if people
don't mind adding another field to uw I could do that?

> >  	vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
> > +	if (cpus_have_final_cap(ARM64_HAS_FPMR)) {
> > +		WARN_ON_ONCE(&current->thread.fpmr + 1 != fpsimd_share_end(fpsimd));

> How can this happen?

It shouldn't, but it'd be bad if it did so I put a check in to make sure
we haven't messed up.

> > +		vcpu->arch.host_fpmr = kern_hyp_va(&current->thread.fpmr);
> > +	}

> We really need to stop piling the save/restore of stuff that isn't
> advertised to the guest.

I'm not clear what you're referencing here?  The feature is advertised
to the guest via the ID registers and in the past you've pushed back on
making things where the state is just a single register like this
optional.  Do you mean that we should be making this conditional on the
guest ID registers?  If that is the case is there a plan for how that's
supposed to work, set flags when kvm_vcpu_run_pid_change() happens for
example?

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Re: [PATCH v3 15/21] KVM: arm64: Support FEAT_FPMR for guests

[Marc Zyngier]

On Thu, 07 Dec 2023 12:30:45 +0000,
Mark Brown <broonie@kernel.org> wrote:
> 
> On Thu, Dec 07, 2023 at 08:39:46AM +0000, Marc Zyngier wrote:
> > Mark Brown <broonie@kernel.org> wrote:
> 
> > >  #define HCRX_GUEST_FLAGS \
> > > -	(HCRX_EL2_SMPME | HCRX_EL2_TCR2En | \
> > > +	(HCRX_EL2_SMPME | HCRX_EL2_TCR2En | HCRX_EL2_EnFPM | \
> 
> > We really should start making all of these things conditional. See
> > below.
> 
> Is there an overarching theory behind how these things are intended to
> work?  I agree with you that I'd have expected more conditionality here,
> I was trying to fit in with the existing pattern.  It's kind of hard to
> follow what the intention is, I think to some extent due to things
> having evolved over time.

The intention is that *everything* becomes conditional, based on both
the host CPU support and the feature set advertised to the guest.
Which means that we don't stuff that isn't advertised to the guest,
and instead make these things UNDEF. Just like on any real CPU
implementation.

>
> > > @@ -517,7 +519,6 @@ struct kvm_vcpu_arch {
> > >  	enum fp_type fp_type;
> > >  	unsigned int sve_max_vl;
> > >  	u64 svcr;
> > > -	u64 fpmr;
> 
> > Why do this change here? Why isn't done like that the first place?
> 
> It didn't seem right to add the register to struct vcpu_sysreg before it
> was handled by KVM.  As referenced in the cover letter normally this
> wouldn't come up because KVM doesn't rely on the host kernel for
> managing register state so we add KVM support then enable the host
> kernel but for FPSIMD we're reusing fpsimd_save() so we need the host
> kernel support to be in place when we enable KVM.

That doesn't explain why you can't be upfront with it and populate the
FPMR entry. In either case, you are wasting a u64.

> 
> > >  	CGT_MDCR_TDE,
> > > @@ -279,6 +281,12 @@ static const struct trap_bits coarse_trap_bits[] = {
> > >  		.mask		= HCR_TTLBOS,
> > >  		.behaviour	= BEHAVE_FORWARD_ANY,
> > >  	},
> > > +	[CGT_HCRX_EnFPM] = {
> > > +		.index		= HCRX_EL2,
> > > +		.value		= HCRX_EL2_EnFPM,
> > > +		.mask		= HCRX_EL2_EnFPM,
> > > +		.behaviour	= BEHAVE_FORWARD_ANY,
> 
> > This looks wrong. HCRX_EL2.EnFPM is an enable bit.
> 
> Right, it's the wrong way round.
> 
> > > +static void *fpsimd_share_end(struct user_fpsimd_state *fpsimd)
> > > +{
> > > +	void *share_end = fpsimd + 1;
> > > +
> > > +	if (cpus_have_final_cap(ARM64_HAS_FPMR))
> > > +		share_end += sizeof(u64);
> > > +
> > > +	return share_end;
> > > +}
> 
> > This is horrible. Why can't you just have a new structure wrapping
> > both user_fpsimd_state and fpmr? This is going to break in subtle
> > ways, just like the SVE/SME stuff.
> 
> I agree that it's not great, the main issue was that fpsimd_state is
> both already embedded in uw for hardened usercopy and very widely
> referenced by exactly which struct it's in so I was taking a guess as to
> what would get the least objections.  The obvious thing would be to add
> FPMR to uw and share the whole thing with the hypervisor, if people
> don't mind adding another field to uw I could do that?

Either that, or you create a KVM-specific structure that contains
these fields. If that results in KVM changes, so be it. But I won't
take this sort of pointer arithmetic that assumes some pre-defined
layout.

> 
> > >  	vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
> > > +	if (cpus_have_final_cap(ARM64_HAS_FPMR)) {
> > > +		WARN_ON_ONCE(&current->thread.fpmr + 1 != fpsimd_share_end(fpsimd));
> 
> > How can this happen?
> 
> It shouldn't, but it'd be bad if it did so I put a check in to make sure
> we haven't messed up.

See my earlier point: you shouldn't have to check if you used a data
structure.

> 
> > > +		vcpu->arch.host_fpmr = kern_hyp_va(&current->thread.fpmr);
> > > +	}
> 
> > We really need to stop piling the save/restore of stuff that isn't
> > advertised to the guest.
> 
> I'm not clear what you're referencing here?  The feature is advertised
> to the guest via the ID registers and in the past you've pushed back on
> making things where the state is just a single register like this
> optional.  Do you mean that we should be making this conditional on the
> guest ID registers?  If that is the case is there a plan for how that's
> supposed to work, set flags when kvm_vcpu_run_pid_change() happens for
> example?

See the beginning of this email. It is high time that we stop enabling
everything by default, because this totally breaks VM migration. We
already have a huge backlog of these things, and I don't want to add
more of it.

Which means that at the very least, enabling *any* feature also comes
with sanitising the state one way or another when this feature is
disabled by userspace.

How this is being done is still a work in progress: my current plan is
based on a set of trap bits that are computed on a per-VM basis, and
some side state that indicates whether the trap handling is for
emulation or feature disabling purpose. This will probably reuse the
NV infrastructure which has an exhaustive list of the sysregs that can
be trapped from EL0/EL1.

At the very least, userspace shouldn't be able to observe the state
that a guest isn't supposed to generate, and we should be mindful of
not creating covert channels.

	M.

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Re: [PATCH v3 15/21] KVM: arm64: Support FEAT_FPMR for guests

[Mark Brown]

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On Thu, Dec 07, 2023 at 02:06:34PM +0000, Marc Zyngier wrote:
> Mark Brown <broonie@kernel.org> wrote:

> > > > @@ -517,7 +519,6 @@ struct kvm_vcpu_arch {
> > > >  	enum fp_type fp_type;
> > > >  	unsigned int sve_max_vl;
> > > >  	u64 svcr;
> > > > -	u64 fpmr;

> > > Why do this change here? Why isn't done like that the first place?

> > It didn't seem right to add the register to struct vcpu_sysreg before it
> > was handled by KVM.  As referenced in the cover letter normally this
> > wouldn't come up because KVM doesn't rely on the host kernel for
> > managing register state so we add KVM support then enable the host
> > kernel but for FPSIMD we're reusing fpsimd_save() so we need the host
> > kernel support to be in place when we enable KVM.

> That doesn't explain why you can't be upfront with it and populate the
> FPMR entry. In either case, you are wasting a u64.

So you'd rather just have the register listed in there as part of the
host support rather than initially excluding it?  Note that the current
series has the same approach as is currently used for SVCR which is in a
similar situation.

> > I agree that it's not great, the main issue was that fpsimd_state is
> > both already embedded in uw for hardened usercopy and very widely
> > referenced by exactly which struct it's in so I was taking a guess as to
> > what would get the least objections.  The obvious thing would be to add
> > FPMR to uw and share the whole thing with the hypervisor, if people
> > don't mind adding another field to uw I could do that?

> Either that, or you create a KVM-specific structure that contains
> these fields. If that results in KVM changes, so be it. But I won't
> take this sort of pointer arithmetic that assumes some pre-defined
> layout.

Moving fpsimd_state would have a big textual impact on the host code and
consequent issues with creating conflicts too so I'd rather avoid that.

> > > We really need to stop piling the save/restore of stuff that isn't
> > > advertised to the guest.

> > I'm not clear what you're referencing here?  The feature is advertised
> > to the guest via the ID registers and in the past you've pushed back on
> > making things where the state is just a single register like this
> > optional.  Do you mean that we should be making this conditional on the
> > guest ID registers?  If that is the case is there a plan for how that's
> > supposed to work, set flags when kvm_vcpu_run_pid_change() happens for
> > example?

> See the beginning of this email. It is high time that we stop enabling
> everything by default, because this totally breaks VM migration. We
> already have a huge backlog of these things, and I don't want to add
> more of it.

> Which means that at the very least, enabling *any* feature also comes
> with sanitising the state one way or another when this feature is
> disabled by userspace.

> How this is being done is still a work in progress: my current plan is
> based on a set of trap bits that are computed on a per-VM basis, and
> some side state that indicates whether the trap handling is for
> emulation or feature disabling purpose. This will probably reuse the
> NV infrastructure which has an exhaustive list of the sysregs that can
> be trapped from EL0/EL1.

> At the very least, userspace shouldn't be able to observe the state
> that a guest isn't supposed to generate, and we should be mindful of
> not creating covert channels.

OK, that does seem much more like what I'd have expected the enablement
of these extra features to look like (and may well simplify a bunch of
the existing trap management) though it is a big change in approach.  It
does greatly expand the scope of what's needed to virtualise the feature
though, and there's a bunch of other in flight serieses that'd be
impacted (eg, POR and GCS) and I'm expecting a bunch of overlap until
the general mechanism gets landed.

Based on that I think it might make sense to push the KVM guest support
for these features out and deal with them separately as part of the new
approach to trap/feature management.  Probably through pulling the KVM
bits to the end of the serieses so they're there for people to see.
Does that sound reasonable to you?

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