From patchwork Tue Nov 14 14:34:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13455374 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CFCDB41232; Tue, 14 Nov 2023 14:35:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="izmal1NH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EEAEEC433B8; Tue, 14 Nov 2023 14:35:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1699972558; bh=8aMhtvWd2U4DgD7OsoWitXafC2Gl0m4G3yGyGq+lQbA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=izmal1NHUcXM258SsY7CAzau7r6omqtbcTWKpJdC7aNgAVS3wrhLv+5d1qme3QBcP IDgnF+/e3KKUiJsrpQB+G0BQpViD9QrnWLxd1vJkxr4IF+Cc2UxrQVBBBYAdRzgekl TBhxtyvL/TAKKWDfa2JsEq0fX9HzMo37VjwFhYZfxAte56nQmMyQKXdl94pePo8jep SHAODwykmnw1G5IZvdajPAjbFZDw9NWo82ItDbjOGMaPZgzmtvGlspacxfazJG+bbc 7aifuiDNRn3XgQ9hGh6NE+Mrps1yes87cQnWH/zXD9IMD5YEWT2rHWM0r45XijTnAx EA0KdNEMD+24w== From: Mark Brown Date: Tue, 14 Nov 2023 14:34:56 +0000 Subject: [PATCH v2 11/21] arm64/fpsimd: Support FEAT_FPMR Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20231114-arm64-2023-dpisa-v2-11-47251894f6a8@kernel.org> References: <20231114-arm64-2023-dpisa-v2-0-47251894f6a8@kernel.org> In-Reply-To: <20231114-arm64-2023-dpisa-v2-0-47251894f6a8@kernel.org> To: Catalin Marinas , Will Deacon , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Jonathan Corbet , Shuah Khan Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Mark Brown X-Mailer: b4 0.13-dev-0438c X-Developer-Signature: v=1; a=openpgp-sha256; l=6717; i=broonie@kernel.org; h=from:subject:message-id; bh=8aMhtvWd2U4DgD7OsoWitXafC2Gl0m4G3yGyGq+lQbA=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBlU4WdDpPp66HYRzBr0f+t44qJWTRJ4dFjYjTu+Ix5 R50HEVmJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZVOFnQAKCRAk1otyXVSH0G/GB/ 9c1CgTjCIp7wxd/CTP4ABHWi2Q4r+evaJgH2ZXNpQhXoEbYq1xymDugpOzV77r3qEmqu9nUmtngDbM vGpaLI1BNZWpxArTK34GBWE0qr2VlDLZ5PuM90YYgiSpOsZwdsx7klRB3eFn4LbsxecMZ91C3wWwM1 mPncgP4C6izwTvnYgnSeZN72flPrV7uOsB+JDzCgtApARTNHj/di5stJnP/D4VrOafeSzjXDMv8aZP 8iYkyibvoU6BFE7xs8EKE/TBvqSbTF+Tn1wTUhZJYXukIZcN515b1SSBh8z1Gi6VOQPdVNIhNRg61c 7XF5lNhKGZ2NOEuMjsdNGOrpzXY6bm X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB 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 --- 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 = ¤t->thread.svcr; + last->fpmr = ¤t->thread.fpmr; last->fp_type = ¤t->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