* [PATCH] arm64: Introduce ISAR6 CPU ID register
@ 2019-12-12 10:14 Anshuman Khandual
2019-12-12 11:43 ` Marc Zyngier
2019-12-12 14:46 ` Mark Rutland
0 siblings, 2 replies; 8+ messages in thread
From: Anshuman Khandual @ 2019-12-12 10:14 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Anshuman Khandual, Catalin Marinas, Will Deacon, Marc Zyngier,
James Morse, Suzuki K Poulose, Mark Rutland, linux-kernel,
kvmarm
This adds basic building blocks required for ISAR6 CPU ID register which
identifies support for various instruction implementation on AArch32 state.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-kernel@vger.kernel.org
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
arch/arm64/include/asm/cpu.h | 1 +
arch/arm64/include/asm/sysreg.h | 9 +++++++++
arch/arm64/kernel/cpufeature.c | 7 ++++++-
arch/arm64/kernel/cpuinfo.c | 1 +
arch/arm64/kvm/sys_regs.c | 2 +-
5 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h
index d72d995..b4a4053 100644
--- a/arch/arm64/include/asm/cpu.h
+++ b/arch/arm64/include/asm/cpu.h
@@ -39,6 +39,7 @@ struct cpuinfo_arm64 {
u32 reg_id_isar3;
u32 reg_id_isar4;
u32 reg_id_isar5;
+ u32 reg_id_isar6;
u32 reg_id_mmfr0;
u32 reg_id_mmfr1;
u32 reg_id_mmfr2;
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 6db3a9b..4fd3327 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -146,6 +146,7 @@
#define SYS_ID_ISAR4_EL1 sys_reg(3, 0, 0, 2, 4)
#define SYS_ID_ISAR5_EL1 sys_reg(3, 0, 0, 2, 5)
#define SYS_ID_MMFR4_EL1 sys_reg(3, 0, 0, 2, 6)
+#define SYS_ID_ISAR6_EL1 sys_reg(3, 0, 0, 2, 7)
#define SYS_MVFR0_EL1 sys_reg(3, 0, 0, 3, 0)
#define SYS_MVFR1_EL1 sys_reg(3, 0, 0, 3, 1)
@@ -683,6 +684,14 @@
#define ID_ISAR5_AES_SHIFT 4
#define ID_ISAR5_SEVL_SHIFT 0
+#define ID_ISAR6_JSCVT_SHIFT 0
+#define ID_ISAR6_DP_SHIFT 4
+#define ID_ISAR6_FHM_SHIFT 8
+#define ID_ISAR6_SB_SHIFT 12
+#define ID_ISAR6_SPECRES_SHIFT 16
+#define ID_ISAR6_BF16_SHIFT 20
+#define ID_ISAR6_I8MM_SHIFT 24
+
#define MVFR0_FPROUND_SHIFT 28
#define MVFR0_FPSHVEC_SHIFT 24
#define MVFR0_FPSQRT_SHIFT 20
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index f344cea..3b9ac8b 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -346,7 +346,7 @@ static const struct arm64_ftr_bits ftr_zcr[] = {
* Common ftr bits for a 32bit register with all hidden, strict
* attributes, with 4bit feature fields and a default safe value of
* 0. Covers the following 32bit registers:
- * id_isar[0-4], id_mmfr[1-3], id_pfr1, mvfr[0-1]
+ * id_isar[0-4, 6], id_mmfr[1-3], id_pfr1, mvfr[0-1]
*/
static const struct arm64_ftr_bits ftr_generic_32bits[] = {
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
@@ -399,6 +399,7 @@ static const struct __ftr_reg_entry {
ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
+ ARM64_FTR_REG(SYS_ID_ISAR6_EL1, ftr_generic_32bits),
/* Op1 = 0, CRn = 0, CRm = 3 */
ARM64_FTR_REG(SYS_MVFR0_EL1, ftr_generic_32bits),
@@ -603,6 +604,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
init_cpu_ftr_reg(SYS_ID_ISAR3_EL1, info->reg_id_isar3);
init_cpu_ftr_reg(SYS_ID_ISAR4_EL1, info->reg_id_isar4);
init_cpu_ftr_reg(SYS_ID_ISAR5_EL1, info->reg_id_isar5);
+ init_cpu_ftr_reg(SYS_ID_ISAR6_EL1, info->reg_id_isar6);
init_cpu_ftr_reg(SYS_ID_MMFR0_EL1, info->reg_id_mmfr0);
init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1);
init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2);
@@ -756,6 +758,8 @@ void update_cpu_features(int cpu,
info->reg_id_isar4, boot->reg_id_isar4);
taint |= check_update_ftr_reg(SYS_ID_ISAR5_EL1, cpu,
info->reg_id_isar5, boot->reg_id_isar5);
+ taint |= check_update_ftr_reg(SYS_ID_ISAR6_EL1, cpu,
+ info->reg_id_isar6, boot->reg_id_isar6);
/*
* Regardless of the value of the AuxReg field, the AIFSR, ADFSR, and
@@ -834,6 +838,7 @@ static u64 __read_sysreg_by_encoding(u32 sys_id)
read_sysreg_case(SYS_ID_ISAR3_EL1);
read_sysreg_case(SYS_ID_ISAR4_EL1);
read_sysreg_case(SYS_ID_ISAR5_EL1);
+ read_sysreg_case(SYS_ID_ISAR6_EL1);
read_sysreg_case(SYS_MVFR0_EL1);
read_sysreg_case(SYS_MVFR1_EL1);
read_sysreg_case(SYS_MVFR2_EL1);
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
index 10121f5..6005d38 100644
--- a/arch/arm64/kernel/cpuinfo.c
+++ b/arch/arm64/kernel/cpuinfo.c
@@ -362,6 +362,7 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
info->reg_id_isar3 = read_cpuid(ID_ISAR3_EL1);
info->reg_id_isar4 = read_cpuid(ID_ISAR4_EL1);
info->reg_id_isar5 = read_cpuid(ID_ISAR5_EL1);
+ info->reg_id_isar6 = read_cpuid(ID_ISAR6_EL1);
info->reg_id_mmfr0 = read_cpuid(ID_MMFR0_EL1);
info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1);
info->reg_id_mmfr2 = read_cpuid(ID_MMFR2_EL1);
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 7dadd24..a6b8ca1 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1424,7 +1424,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
ID_SANITISED(ID_ISAR4_EL1),
ID_SANITISED(ID_ISAR5_EL1),
ID_SANITISED(ID_MMFR4_EL1),
- ID_UNALLOCATED(2,7),
+ ID_SANITISED(ID_ISAR6_EL1),
/* CRm=3 */
ID_SANITISED(MVFR0_EL1),
--
2.7.4
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] arm64: Introduce ISAR6 CPU ID register
2019-12-12 10:14 [PATCH] arm64: Introduce ISAR6 CPU ID register Anshuman Khandual
@ 2019-12-12 11:43 ` Marc Zyngier
2019-12-13 3:20 ` Anshuman Khandual
2019-12-12 14:46 ` Mark Rutland
1 sibling, 1 reply; 8+ messages in thread
From: Marc Zyngier @ 2019-12-12 11:43 UTC (permalink / raw)
To: Anshuman Khandual
Cc: linux-arm-kernel, Catalin Marinas, linux-kernel, Will Deacon, kvmarm
On 2019-12-12 10:14, Anshuman Khandual wrote:
> This adds basic building blocks required for ISAR6 CPU ID register
> which
> identifies support for various instruction implementation on AArch32
> state.
nit: the register name is ID_ISAR6.
>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Marc Zyngier <maz@kernel.org>
> Cc: James Morse <james.morse@arm.com>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: linux-kernel@vger.kernel.org
> Cc: kvmarm@lists.cs.columbia.edu
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> arch/arm64/include/asm/cpu.h | 1 +
> arch/arm64/include/asm/sysreg.h | 9 +++++++++
> arch/arm64/kernel/cpufeature.c | 7 ++++++-
> arch/arm64/kernel/cpuinfo.c | 1 +
> arch/arm64/kvm/sys_regs.c | 2 +-
> 5 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/include/asm/cpu.h
> b/arch/arm64/include/asm/cpu.h
> index d72d995..b4a4053 100644
> --- a/arch/arm64/include/asm/cpu.h
> +++ b/arch/arm64/include/asm/cpu.h
> @@ -39,6 +39,7 @@ struct cpuinfo_arm64 {
> u32 reg_id_isar3;
> u32 reg_id_isar4;
> u32 reg_id_isar5;
> + u32 reg_id_isar6;
> u32 reg_id_mmfr0;
> u32 reg_id_mmfr1;
> u32 reg_id_mmfr2;
> diff --git a/arch/arm64/include/asm/sysreg.h
> b/arch/arm64/include/asm/sysreg.h
> index 6db3a9b..4fd3327 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -146,6 +146,7 @@
> #define SYS_ID_ISAR4_EL1 sys_reg(3, 0, 0, 2, 4)
> #define SYS_ID_ISAR5_EL1 sys_reg(3, 0, 0, 2, 5)
> #define SYS_ID_MMFR4_EL1 sys_reg(3, 0, 0, 2, 6)
> +#define SYS_ID_ISAR6_EL1 sys_reg(3, 0, 0, 2, 7)
>
> #define SYS_MVFR0_EL1 sys_reg(3, 0, 0, 3, 0)
> #define SYS_MVFR1_EL1 sys_reg(3, 0, 0, 3, 1)
> @@ -683,6 +684,14 @@
> #define ID_ISAR5_AES_SHIFT 4
> #define ID_ISAR5_SEVL_SHIFT 0
>
> +#define ID_ISAR6_JSCVT_SHIFT 0
> +#define ID_ISAR6_DP_SHIFT 4
> +#define ID_ISAR6_FHM_SHIFT 8
> +#define ID_ISAR6_SB_SHIFT 12
> +#define ID_ISAR6_SPECRES_SHIFT 16
> +#define ID_ISAR6_BF16_SHIFT 20
> +#define ID_ISAR6_I8MM_SHIFT 24
I couldn't find the last two items in the E.a revision of the ARMv8
ARM.
I guess they are for post 8.5 revisions of the architecture?
> +
> #define MVFR0_FPROUND_SHIFT 28
> #define MVFR0_FPSHVEC_SHIFT 24
> #define MVFR0_FPSQRT_SHIFT 20
> diff --git a/arch/arm64/kernel/cpufeature.c
> b/arch/arm64/kernel/cpufeature.c
> index f344cea..3b9ac8b 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -346,7 +346,7 @@ static const struct arm64_ftr_bits ftr_zcr[] = {
> * Common ftr bits for a 32bit register with all hidden, strict
> * attributes, with 4bit feature fields and a default safe value of
> * 0. Covers the following 32bit registers:
> - * id_isar[0-4], id_mmfr[1-3], id_pfr1, mvfr[0-1]
> + * id_isar[0-4, 6], id_mmfr[1-3], id_pfr1, mvfr[0-1]
> */
> static const struct arm64_ftr_bits ftr_generic_32bits[] = {
> ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
> @@ -399,6 +399,7 @@ static const struct __ftr_reg_entry {
> ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
> ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
> ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
> + ARM64_FTR_REG(SYS_ID_ISAR6_EL1, ftr_generic_32bits),
>
> /* Op1 = 0, CRn = 0, CRm = 3 */
> ARM64_FTR_REG(SYS_MVFR0_EL1, ftr_generic_32bits),
> @@ -603,6 +604,7 @@ void __init init_cpu_features(struct
> cpuinfo_arm64 *info)
> init_cpu_ftr_reg(SYS_ID_ISAR3_EL1, info->reg_id_isar3);
> init_cpu_ftr_reg(SYS_ID_ISAR4_EL1, info->reg_id_isar4);
> init_cpu_ftr_reg(SYS_ID_ISAR5_EL1, info->reg_id_isar5);
> + init_cpu_ftr_reg(SYS_ID_ISAR6_EL1, info->reg_id_isar6);
> init_cpu_ftr_reg(SYS_ID_MMFR0_EL1, info->reg_id_mmfr0);
> init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1);
> init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2);
> @@ -756,6 +758,8 @@ void update_cpu_features(int cpu,
> info->reg_id_isar4, boot->reg_id_isar4);
> taint |= check_update_ftr_reg(SYS_ID_ISAR5_EL1, cpu,
> info->reg_id_isar5, boot->reg_id_isar5);
> + taint |= check_update_ftr_reg(SYS_ID_ISAR6_EL1, cpu,
> + info->reg_id_isar6, boot->reg_id_isar6);
>
> /*
> * Regardless of the value of the AuxReg field, the AIFSR, ADFSR,
> and
> @@ -834,6 +838,7 @@ static u64 __read_sysreg_by_encoding(u32 sys_id)
> read_sysreg_case(SYS_ID_ISAR3_EL1);
> read_sysreg_case(SYS_ID_ISAR4_EL1);
> read_sysreg_case(SYS_ID_ISAR5_EL1);
> + read_sysreg_case(SYS_ID_ISAR6_EL1);
> read_sysreg_case(SYS_MVFR0_EL1);
> read_sysreg_case(SYS_MVFR1_EL1);
> read_sysreg_case(SYS_MVFR2_EL1);
> diff --git a/arch/arm64/kernel/cpuinfo.c
> b/arch/arm64/kernel/cpuinfo.c
> index 10121f5..6005d38 100644
> --- a/arch/arm64/kernel/cpuinfo.c
> +++ b/arch/arm64/kernel/cpuinfo.c
> @@ -362,6 +362,7 @@ static void __cpuinfo_store_cpu(struct
> cpuinfo_arm64 *info)
> info->reg_id_isar3 = read_cpuid(ID_ISAR3_EL1);
> info->reg_id_isar4 = read_cpuid(ID_ISAR4_EL1);
> info->reg_id_isar5 = read_cpuid(ID_ISAR5_EL1);
> + info->reg_id_isar6 = read_cpuid(ID_ISAR6_EL1);
> info->reg_id_mmfr0 = read_cpuid(ID_MMFR0_EL1);
> info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1);
> info->reg_id_mmfr2 = read_cpuid(ID_MMFR2_EL1);
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 7dadd24..a6b8ca1 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1424,7 +1424,7 @@ static const struct sys_reg_desc
> sys_reg_descs[] = {
> ID_SANITISED(ID_ISAR4_EL1),
> ID_SANITISED(ID_ISAR5_EL1),
> ID_SANITISED(ID_MMFR4_EL1),
> - ID_UNALLOCATED(2,7),
> + ID_SANITISED(ID_ISAR6_EL1),
>
> /* CRm=3 */
> ID_SANITISED(MVFR0_EL1),
Otherwise,
Acked-by: Marc Zyngier <maz@kernel.org>
M.
--
Jazz is not dead. It just smells funny...
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] arm64: Introduce ISAR6 CPU ID register
2019-12-12 10:14 [PATCH] arm64: Introduce ISAR6 CPU ID register Anshuman Khandual
2019-12-12 11:43 ` Marc Zyngier
@ 2019-12-12 14:46 ` Mark Rutland
2019-12-12 15:22 ` Suzuki Kuruppassery Poulose
1 sibling, 1 reply; 8+ messages in thread
From: Mark Rutland @ 2019-12-12 14:46 UTC (permalink / raw)
To: Anshuman Khandual
Cc: linux-arm-kernel, Catalin Marinas, Will Deacon, Marc Zyngier,
James Morse, Suzuki K Poulose, linux-kernel, kvmarm
On Thu, Dec 12, 2019 at 03:44:23PM +0530, Anshuman Khandual wrote:
> +#define ID_ISAR6_JSCVT_SHIFT 0
> +#define ID_ISAR6_DP_SHIFT 4
> +#define ID_ISAR6_FHM_SHIFT 8
> +#define ID_ISAR6_SB_SHIFT 12
> +#define ID_ISAR6_SPECRES_SHIFT 16
> +#define ID_ISAR6_BF16_SHIFT 20
> +#define ID_ISAR6_I8MM_SHIFT 24
> @@ -399,6 +399,7 @@ static const struct __ftr_reg_entry {
> ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
> ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
> ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
> + ARM64_FTR_REG(SYS_ID_ISAR6_EL1, ftr_generic_32bits),
Using ftr_generic_32bits exposes the lowest-common-denominator for all
4-bit fields in the register, and I don't think that's the right thing
to do here, because:
* We have no idea what ID_ISAR6 bits [31:28] may mean in future.
* AFAICT, the instructions described by ID_ISAR6.SPECRES (from the
ARMv8.0-PredInv extension) operate on the local PE and are not
broadcast. To make those work as a guest expects, the host will need
to do additional things (e.g. to preserve that illusion when a vCPU is
migrated from one pCPU to another and back).
Given that, think we should add an explicit ftr_id_isar6 which only
exposes the fields that we're certain are safe to expose to a guest
(i.e. without SPECRES).
Thanks,
Mark.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] arm64: Introduce ISAR6 CPU ID register
2019-12-12 14:46 ` Mark Rutland
@ 2019-12-12 15:22 ` Suzuki Kuruppassery Poulose
2019-12-12 16:31 ` Mark Rutland
2019-12-13 3:29 ` Anshuman Khandual
0 siblings, 2 replies; 8+ messages in thread
From: Suzuki Kuruppassery Poulose @ 2019-12-12 15:22 UTC (permalink / raw)
To: Mark Rutland, Anshuman Khandual
Cc: linux-arm-kernel, Catalin Marinas, Will Deacon, Marc Zyngier,
James Morse, linux-kernel, kvmarm
On 12/12/2019 14:46, Mark Rutland wrote:
> On Thu, Dec 12, 2019 at 03:44:23PM +0530, Anshuman Khandual wrote:
>> +#define ID_ISAR6_JSCVT_SHIFT 0
>> +#define ID_ISAR6_DP_SHIFT 4
>> +#define ID_ISAR6_FHM_SHIFT 8
>> +#define ID_ISAR6_SB_SHIFT 12
>> +#define ID_ISAR6_SPECRES_SHIFT 16
>> +#define ID_ISAR6_BF16_SHIFT 20
>> +#define ID_ISAR6_I8MM_SHIFT 24
>
>> @@ -399,6 +399,7 @@ static const struct __ftr_reg_entry {
>> ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
>> ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
>> ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
>
>> + ARM64_FTR_REG(SYS_ID_ISAR6_EL1, ftr_generic_32bits),
>
> Using ftr_generic_32bits exposes the lowest-common-denominator for all
> 4-bit fields in the register, and I don't think that's the right thing
> to do here, because:
>
> * We have no idea what ID_ISAR6 bits [31:28] may mean in future.
>
> * AFAICT, the instructions described by ID_ISAR6.SPECRES (from the
> ARMv8.0-PredInv extension) operate on the local PE and are not
> broadcast. To make those work as a guest expects, the host will need
> to do additional things (e.g. to preserve that illusion when a vCPU is
> migrated from one pCPU to another and back).
>
> Given that, think we should add an explicit ftr_id_isar6 which only
> exposes the fields that we're certain are safe to expose to a guest
> (i.e. without SPECRES).
Agree. Thanks for pointing this out. I recommended the usage of
generic_32bits table without actually looking at the feature
definitions.
Anshuman,
Sorry about this.
Cheers
Suzuki
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] arm64: Introduce ISAR6 CPU ID register
2019-12-12 15:22 ` Suzuki Kuruppassery Poulose
@ 2019-12-12 16:31 ` Mark Rutland
2019-12-18 5:53 ` Anshuman Khandual
2019-12-13 3:29 ` Anshuman Khandual
1 sibling, 1 reply; 8+ messages in thread
From: Mark Rutland @ 2019-12-12 16:31 UTC (permalink / raw)
To: Suzuki Kuruppassery Poulose
Cc: Anshuman Khandual, linux-arm-kernel, Catalin Marinas,
Will Deacon, Marc Zyngier, James Morse, linux-kernel, kvmarm
On Thu, Dec 12, 2019 at 03:22:13PM +0000, Suzuki Kuruppassery Poulose wrote:
> On 12/12/2019 14:46, Mark Rutland wrote:
> > On Thu, Dec 12, 2019 at 03:44:23PM +0530, Anshuman Khandual wrote:
> > > +#define ID_ISAR6_JSCVT_SHIFT 0
> > > +#define ID_ISAR6_DP_SHIFT 4
> > > +#define ID_ISAR6_FHM_SHIFT 8
> > > +#define ID_ISAR6_SB_SHIFT 12
> > > +#define ID_ISAR6_SPECRES_SHIFT 16
> > > +#define ID_ISAR6_BF16_SHIFT 20
> > > +#define ID_ISAR6_I8MM_SHIFT 24
> >
> > > @@ -399,6 +399,7 @@ static const struct __ftr_reg_entry {
> > > ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
> > > ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
> > > ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
> >
> > > + ARM64_FTR_REG(SYS_ID_ISAR6_EL1, ftr_generic_32bits),
> >
> > Using ftr_generic_32bits exposes the lowest-common-denominator for all
> > 4-bit fields in the register, and I don't think that's the right thing
> > to do here, because:
> >
> > * We have no idea what ID_ISAR6 bits [31:28] may mean in future.
> >
> > * AFAICT, the instructions described by ID_ISAR6.SPECRES (from the
> > ARMv8.0-PredInv extension) operate on the local PE and are not
> > broadcast. To make those work as a guest expects, the host will need
> > to do additional things (e.g. to preserve that illusion when a vCPU is
> > migrated from one pCPU to another and back).
> >
> > Given that, think we should add an explicit ftr_id_isar6 which only
> > exposes the fields that we're certain are safe to expose to a guest
> > (i.e. without SPECRES).
>
> Agree. Thanks for pointing this out. I recommended the usage of
> generic_32bits table without actually looking at the feature
> definitions.
No worries; this is /really/ easy to miss!
Looking again, comparing to ARM DDI 0487E.a, there are a few other
things we should probably sort out:
* ID_DFR0 fields need more thought; we should limit what we expose here.
I don't think it's valid for us to expose TraceFilt, and I suspect we
need to add capping for debug features we currently emulate.
* ID_ISAR0[31:28] are RES0 in ARMv8, Reserved/UNK in ARMv7.
We should probably ftr_id_isar0 so we can hide those bits.
* ID_ISAR5[23:10] are RES0
We handle this already! :)
* ID_MMFR4.SpecSEI should be trated as higher safe.
We should update ftr_id_mmfr4 to handle this and other fields.
* ID_PFR0 is missing DIT and CSV2
We should probably add these (but neither RAS not AMU).
* ID_PFR2 is missing
We should probably add this for SSBS and CSV3.
Thanks,
Mark.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] arm64: Introduce ISAR6 CPU ID register
2019-12-12 11:43 ` Marc Zyngier
@ 2019-12-13 3:20 ` Anshuman Khandual
0 siblings, 0 replies; 8+ messages in thread
From: Anshuman Khandual @ 2019-12-13 3:20 UTC (permalink / raw)
To: Marc Zyngier
Cc: linux-arm-kernel, Catalin Marinas, linux-kernel, Will Deacon, kvmarm
On 12/12/2019 05:13 PM, Marc Zyngier wrote:
> On 2019-12-12 10:14, Anshuman Khandual wrote:
>> This adds basic building blocks required for ISAR6 CPU ID register which
>> identifies support for various instruction implementation on AArch32 state.
>
> nit: the register name is ID_ISAR6.
Sure, will change.
>
>>
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Will Deacon <will@kernel.org>
>> Cc: Marc Zyngier <maz@kernel.org>
>> Cc: James Morse <james.morse@arm.com>
>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Cc: linux-kernel@vger.kernel.org
>> Cc: kvmarm@lists.cs.columbia.edu
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>> arch/arm64/include/asm/cpu.h | 1 +
>> arch/arm64/include/asm/sysreg.h | 9 +++++++++
>> arch/arm64/kernel/cpufeature.c | 7 ++++++-
>> arch/arm64/kernel/cpuinfo.c | 1 +
>> arch/arm64/kvm/sys_regs.c | 2 +-
>> 5 files changed, 18 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h
>> index d72d995..b4a4053 100644
>> --- a/arch/arm64/include/asm/cpu.h
>> +++ b/arch/arm64/include/asm/cpu.h
>> @@ -39,6 +39,7 @@ struct cpuinfo_arm64 {
>> u32 reg_id_isar3;
>> u32 reg_id_isar4;
>> u32 reg_id_isar5;
>> + u32 reg_id_isar6;
>> u32 reg_id_mmfr0;
>> u32 reg_id_mmfr1;
>> u32 reg_id_mmfr2;
>> diff --git a/arch/arm64/include/asm/sysreg.h
>> b/arch/arm64/include/asm/sysreg.h
>> index 6db3a9b..4fd3327 100644
>> --- a/arch/arm64/include/asm/sysreg.h
>> +++ b/arch/arm64/include/asm/sysreg.h
>> @@ -146,6 +146,7 @@
>> #define SYS_ID_ISAR4_EL1 sys_reg(3, 0, 0, 2, 4)
>> #define SYS_ID_ISAR5_EL1 sys_reg(3, 0, 0, 2, 5)
>> #define SYS_ID_MMFR4_EL1 sys_reg(3, 0, 0, 2, 6)
>> +#define SYS_ID_ISAR6_EL1 sys_reg(3, 0, 0, 2, 7)
>>
>> #define SYS_MVFR0_EL1 sys_reg(3, 0, 0, 3, 0)
>> #define SYS_MVFR1_EL1 sys_reg(3, 0, 0, 3, 1)
>> @@ -683,6 +684,14 @@
>> #define ID_ISAR5_AES_SHIFT 4
>> #define ID_ISAR5_SEVL_SHIFT 0
>>
>> +#define ID_ISAR6_JSCVT_SHIFT 0
>> +#define ID_ISAR6_DP_SHIFT 4
>> +#define ID_ISAR6_FHM_SHIFT 8
>> +#define ID_ISAR6_SB_SHIFT 12
>> +#define ID_ISAR6_SPECRES_SHIFT 16
>> +#define ID_ISAR6_BF16_SHIFT 20
>> +#define ID_ISAR6_I8MM_SHIFT 24
>
> I couldn't find the last two items in the E.a revision of the ARMv8 ARM.
> I guess they are for post 8.5 revisions of the architecture?
Yes.
>
>> +
>> #define MVFR0_FPROUND_SHIFT 28
>> #define MVFR0_FPSHVEC_SHIFT 24
>> #define MVFR0_FPSQRT_SHIFT 20
>> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
>> index f344cea..3b9ac8b 100644
>> --- a/arch/arm64/kernel/cpufeature.c
>> +++ b/arch/arm64/kernel/cpufeature.c
>> @@ -346,7 +346,7 @@ static const struct arm64_ftr_bits ftr_zcr[] = {
>> * Common ftr bits for a 32bit register with all hidden, strict
>> * attributes, with 4bit feature fields and a default safe value of
>> * 0. Covers the following 32bit registers:
>> - * id_isar[0-4], id_mmfr[1-3], id_pfr1, mvfr[0-1]
>> + * id_isar[0-4, 6], id_mmfr[1-3], id_pfr1, mvfr[0-1]
>> */
>> static const struct arm64_ftr_bits ftr_generic_32bits[] = {
>> ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
>> @@ -399,6 +399,7 @@ static const struct __ftr_reg_entry {
>> ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
>> ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
>> ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
>> + ARM64_FTR_REG(SYS_ID_ISAR6_EL1, ftr_generic_32bits),
>>
>> /* Op1 = 0, CRn = 0, CRm = 3 */
>> ARM64_FTR_REG(SYS_MVFR0_EL1, ftr_generic_32bits),
>> @@ -603,6 +604,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
>> init_cpu_ftr_reg(SYS_ID_ISAR3_EL1, info->reg_id_isar3);
>> init_cpu_ftr_reg(SYS_ID_ISAR4_EL1, info->reg_id_isar4);
>> init_cpu_ftr_reg(SYS_ID_ISAR5_EL1, info->reg_id_isar5);
>> + init_cpu_ftr_reg(SYS_ID_ISAR6_EL1, info->reg_id_isar6);
>> init_cpu_ftr_reg(SYS_ID_MMFR0_EL1, info->reg_id_mmfr0);
>> init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1);
>> init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2);
>> @@ -756,6 +758,8 @@ void update_cpu_features(int cpu,
>> info->reg_id_isar4, boot->reg_id_isar4);
>> taint |= check_update_ftr_reg(SYS_ID_ISAR5_EL1, cpu,
>> info->reg_id_isar5, boot->reg_id_isar5);
>> + taint |= check_update_ftr_reg(SYS_ID_ISAR6_EL1, cpu,
>> + info->reg_id_isar6, boot->reg_id_isar6);
>>
>> /*
>> * Regardless of the value of the AuxReg field, the AIFSR, ADFSR, and
>> @@ -834,6 +838,7 @@ static u64 __read_sysreg_by_encoding(u32 sys_id)
>> read_sysreg_case(SYS_ID_ISAR3_EL1);
>> read_sysreg_case(SYS_ID_ISAR4_EL1);
>> read_sysreg_case(SYS_ID_ISAR5_EL1);
>> + read_sysreg_case(SYS_ID_ISAR6_EL1);
>> read_sysreg_case(SYS_MVFR0_EL1);
>> read_sysreg_case(SYS_MVFR1_EL1);
>> read_sysreg_case(SYS_MVFR2_EL1);
>> diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
>> index 10121f5..6005d38 100644
>> --- a/arch/arm64/kernel/cpuinfo.c
>> +++ b/arch/arm64/kernel/cpuinfo.c
>> @@ -362,6 +362,7 @@ static void __cpuinfo_store_cpu(struct
>> cpuinfo_arm64 *info)
>> info->reg_id_isar3 = read_cpuid(ID_ISAR3_EL1);
>> info->reg_id_isar4 = read_cpuid(ID_ISAR4_EL1);
>> info->reg_id_isar5 = read_cpuid(ID_ISAR5_EL1);
>> + info->reg_id_isar6 = read_cpuid(ID_ISAR6_EL1);
>> info->reg_id_mmfr0 = read_cpuid(ID_MMFR0_EL1);
>> info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1);
>> info->reg_id_mmfr2 = read_cpuid(ID_MMFR2_EL1);
>> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
>> index 7dadd24..a6b8ca1 100644
>> --- a/arch/arm64/kvm/sys_regs.c
>> +++ b/arch/arm64/kvm/sys_regs.c
>> @@ -1424,7 +1424,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>> ID_SANITISED(ID_ISAR4_EL1),
>> ID_SANITISED(ID_ISAR5_EL1),
>> ID_SANITISED(ID_MMFR4_EL1),
>> - ID_UNALLOCATED(2,7),
>> + ID_SANITISED(ID_ISAR6_EL1),
>>
>> /* CRm=3 */
>> ID_SANITISED(MVFR0_EL1),
>
> Otherwise,
>
> Acked-by: Marc Zyngier <maz@kernel.org>
>
> M.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] arm64: Introduce ISAR6 CPU ID register
2019-12-12 15:22 ` Suzuki Kuruppassery Poulose
2019-12-12 16:31 ` Mark Rutland
@ 2019-12-13 3:29 ` Anshuman Khandual
1 sibling, 0 replies; 8+ messages in thread
From: Anshuman Khandual @ 2019-12-13 3:29 UTC (permalink / raw)
To: Suzuki Kuruppassery Poulose, Mark Rutland
Cc: linux-arm-kernel, Catalin Marinas, Will Deacon, Marc Zyngier,
James Morse, linux-kernel, kvmarm
On 12/12/2019 08:52 PM, Suzuki Kuruppassery Poulose wrote:
> On 12/12/2019 14:46, Mark Rutland wrote:
>> On Thu, Dec 12, 2019 at 03:44:23PM +0530, Anshuman Khandual wrote:
>>> +#define ID_ISAR6_JSCVT_SHIFT 0
>>> +#define ID_ISAR6_DP_SHIFT 4
>>> +#define ID_ISAR6_FHM_SHIFT 8
>>> +#define ID_ISAR6_SB_SHIFT 12
>>> +#define ID_ISAR6_SPECRES_SHIFT 16
>>> +#define ID_ISAR6_BF16_SHIFT 20
>>> +#define ID_ISAR6_I8MM_SHIFT 24
>>
>>> @@ -399,6 +399,7 @@ static const struct __ftr_reg_entry {
>>> ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
>>> ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
>>> ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
>>
>>> + ARM64_FTR_REG(SYS_ID_ISAR6_EL1, ftr_generic_32bits),
>>
>> Using ftr_generic_32bits exposes the lowest-common-denominator for all
>> 4-bit fields in the register, and I don't think that's the right thing
>> to do here, because:
>>
>> * We have no idea what ID_ISAR6 bits [31:28] may mean in future.
>>
>> * AFAICT, the instructions described by ID_ISAR6.SPECRES (from the
>> ARMv8.0-PredInv extension) operate on the local PE and are not
>> broadcast. To make those work as a guest expects, the host will need
>> to do additional things (e.g. to preserve that illusion when a vCPU is
>> migrated from one pCPU to another and back).
>>
>> Given that, think we should add an explicit ftr_id_isar6 which only
>> exposes the fields that we're certain are safe to expose to a guest
>> (i.e. without SPECRES).
>
> Agree. Thanks for pointing this out. I recommended the usage of
> generic_32bits table without actually looking at the feature
> definitions.
>
> Anshuman,
>
> Sorry about this.
Not a problem, will add an explicit definition for ftr_id_isar6 with
all features except SPECRES as Mark had pointed put.
>
> Cheers
> Suzuki
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] arm64: Introduce ISAR6 CPU ID register
2019-12-12 16:31 ` Mark Rutland
@ 2019-12-18 5:53 ` Anshuman Khandual
0 siblings, 0 replies; 8+ messages in thread
From: Anshuman Khandual @ 2019-12-18 5:53 UTC (permalink / raw)
To: Mark Rutland, Suzuki Kuruppassery Poulose
Cc: linux-arm-kernel, Catalin Marinas, Will Deacon, Marc Zyngier,
James Morse, linux-kernel, kvmarm
On 12/12/2019 10:01 PM, Mark Rutland wrote:
> On Thu, Dec 12, 2019 at 03:22:13PM +0000, Suzuki Kuruppassery Poulose wrote:
>> On 12/12/2019 14:46, Mark Rutland wrote:
>>> On Thu, Dec 12, 2019 at 03:44:23PM +0530, Anshuman Khandual wrote:
>>>> +#define ID_ISAR6_JSCVT_SHIFT 0
>>>> +#define ID_ISAR6_DP_SHIFT 4
>>>> +#define ID_ISAR6_FHM_SHIFT 8
>>>> +#define ID_ISAR6_SB_SHIFT 12
>>>> +#define ID_ISAR6_SPECRES_SHIFT 16
>>>> +#define ID_ISAR6_BF16_SHIFT 20
>>>> +#define ID_ISAR6_I8MM_SHIFT 24
>>>
>>>> @@ -399,6 +399,7 @@ static const struct __ftr_reg_entry {
>>>> ARM64_FTR_REG(SYS_ID_ISAR4_EL1, ftr_generic_32bits),
>>>> ARM64_FTR_REG(SYS_ID_ISAR5_EL1, ftr_id_isar5),
>>>> ARM64_FTR_REG(SYS_ID_MMFR4_EL1, ftr_id_mmfr4),
>>>
>>>> + ARM64_FTR_REG(SYS_ID_ISAR6_EL1, ftr_generic_32bits),
>>>
>>> Using ftr_generic_32bits exposes the lowest-common-denominator for all
>>> 4-bit fields in the register, and I don't think that's the right thing
>>> to do here, because:
>>>
>>> * We have no idea what ID_ISAR6 bits [31:28] may mean in future.
>>>
>>> * AFAICT, the instructions described by ID_ISAR6.SPECRES (from the
>>> ARMv8.0-PredInv extension) operate on the local PE and are not
>>> broadcast. To make those work as a guest expects, the host will need
>>> to do additional things (e.g. to preserve that illusion when a vCPU is
>>> migrated from one pCPU to another and back).
>>>
>>> Given that, think we should add an explicit ftr_id_isar6 which only
>>> exposes the fields that we're certain are safe to expose to a guest
>>> (i.e. without SPECRES).
>>
>> Agree. Thanks for pointing this out. I recommended the usage of
>> generic_32bits table without actually looking at the feature
>> definitions.
>
> No worries; this is /really/ easy to miss!
>
> Looking again, comparing to ARM DDI 0487E.a, there are a few other
> things we should probably sort out:
>
> * ID_DFR0 fields need more thought; we should limit what we expose here.
> I don't think it's valid for us to expose TraceFilt, and I suspect we
Sure, will go ahead and drop TraceFilt [28..31] from ID_DFR0 register.
> need to add capping for debug features we currently emulate.
Could you please elaborate ?
>
> * ID_ISAR0[31:28] are RES0 in ARMv8, Reserved/UNK in ARMv7.
> We should probably ftr_id_isar0 so we can hide those bits.
Sure, will do.
>
> * ID_ISAR5[23:10] are RES0
> We handle this already! :)
I may be missing something here but some of these fields are already there.
#define ID_ISAR5_RDM_SHIFT 24
#define ID_ISAR5_CRC32_SHIFT 16
#define ID_ISAR5_SHA2_SHIFT 12
#define ID_ISAR5_SHA1_SHIFT 8
#define ID_ISAR5_AES_SHIFT 4
#define ID_ISAR5_SEVL_SHIFT 0
static const struct arm64_ftr_bits ftr_id_isar5[] = {
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_RDM_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_CRC32_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SHA2_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SHA1_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_AES_SHIFT, 4, 0),
ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR5_SEVL_SHIFT, 4, 0),
ARM64_FTR_END,
};
>
> * ID_MMFR4.SpecSEI should be trated as higher safe.
> We should update ftr_id_mmfr4 to handle this and other fields.
Sure but should we also export other fields as higher safe in there ?
>
> * ID_PFR0 is missing DIT and CSV2
> We should probably add these (but neither RAS not AMU).
Sure, will do.
>
> * ID_PFR2 is missing
> We should probably add this for SSBS and CSV3.
Sure but should we add corresponding ID_AA64PFR2_EL1 register as well ?
>
> Thanks,
> Mark.
>
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2019-12-18 5:53 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
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2019-12-12 10:14 [PATCH] arm64: Introduce ISAR6 CPU ID register Anshuman Khandual
2019-12-12 11:43 ` Marc Zyngier
2019-12-13 3:20 ` Anshuman Khandual
2019-12-12 14:46 ` Mark Rutland
2019-12-12 15:22 ` Suzuki Kuruppassery Poulose
2019-12-12 16:31 ` Mark Rutland
2019-12-18 5:53 ` Anshuman Khandual
2019-12-13 3:29 ` Anshuman Khandual
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