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Thu, 11 Mar 2021 19:36:57 +0000 Received: from mail.kernel.org ([198.145.29.99]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lKR72-00A0kl-PB for linux-arm-kernel@lists.infradead.org; Thu, 11 Mar 2021 19:36:53 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id A466864F6A; Thu, 11 Mar 2021 19:36:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615491406; bh=63tmpZ5mQVPPLqeqb+wmvXJ9fc25KQP2XqeO4yS0/jY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HZ4y5yX6mn85uBntb/Oq3wAGEJJCLmygUsHwJIFJt8aZbeHP68kV0RI1X2JsB6N5o 49c1rXqLbxLQbmSX6swwoqbCyZRSPEB5XKf5xgNmJ6QVeVgIQ8qggREs7IaM4rtLzD 0fbE0klrepnYrK7cXPJw2tPS5DMQwNll52VB1fVyq6/XUzfKJMX2GObPRra9MlA7O0 +JipwV5Hd8BT5aiYHcUAin6pzlh6ulg+4b0xPV5IkdeNIFgVkwhQnryfq+z1Te5snW Wx+cY5oxlLYgXErbxu+iZmd0dn7QWDy6A4dcYHxYH6VLg5VbmVxb1GmhR1B6ykzYxu weHYTYT+NbqLQ== Date: Thu, 11 Mar 2021 19:36:39 +0000 From: Will Deacon To: Quentin Perret Cc: catalin.marinas@arm.com, maz@kernel.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, android-kvm@google.com, linux-kernel@vger.kernel.org, kernel-team@android.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, tabba@google.com, mark.rutland@arm.com, dbrazdil@google.com, mate.toth-pal@arm.com, seanjc@google.com, robh+dt@kernel.org, ardb@kernel.org Subject: Re: [PATCH v4 13/34] KVM: arm64: Enable access to sanitized CPU features at EL2 Message-ID: <20210311193638.GE31586@willie-the-truck> References: <20210310175751.3320106-1-qperret@google.com> <20210310175751.3320106-14-qperret@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210310175751.3320106-14-qperret@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210311_193650_534665_1C26FC05 X-CRM114-Status: GOOD ( 28.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Mar 10, 2021 at 05:57:30PM +0000, Quentin Perret wrote: > Introduce the infrastructure in KVM enabling to copy CPU feature > registers into EL2-owned data-structures, to allow reading sanitised > values directly at EL2 in nVHE. > > Given that only a subset of these features are being read by the > hypervisor, the ones that need to be copied are to be listed under > together with the name of the nVHE variable that > will hold the copy. > > While at it, introduce the first user of this infrastructure by > implementing __flush_dcache_area at EL2, which needs > arm64_ftr_reg_ctrel0. > > Signed-off-by: Quentin Perret > --- > arch/arm64/include/asm/cpufeature.h | 1 + > arch/arm64/include/asm/kvm_cpufeature.h | 17 +++++++++++++++++ > arch/arm64/include/asm/kvm_host.h | 4 ++++ > arch/arm64/kernel/cpufeature.c | 13 +++++++++++++ > arch/arm64/kvm/hyp/nvhe/Makefile | 3 ++- > arch/arm64/kvm/hyp/nvhe/cache.S | 13 +++++++++++++ > arch/arm64/kvm/hyp/nvhe/cpufeature.c | 8 ++++++++ > arch/arm64/kvm/sys_regs.c | 21 +++++++++++++++++++++ > 8 files changed, 79 insertions(+), 1 deletion(-) > create mode 100644 arch/arm64/include/asm/kvm_cpufeature.h > create mode 100644 arch/arm64/kvm/hyp/nvhe/cache.S > create mode 100644 arch/arm64/kvm/hyp/nvhe/cpufeature.c > > diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h > index 61177bac49fa..a85cea2cac57 100644 > --- a/arch/arm64/include/asm/cpufeature.h > +++ b/arch/arm64/include/asm/cpufeature.h > @@ -607,6 +607,7 @@ void check_local_cpu_capabilities(void); > > u64 read_sanitised_ftr_reg(u32 id); > u64 __read_sysreg_by_encoding(u32 sys_id); > +int copy_ftr_reg(u32 id, struct arm64_ftr_reg *dst); > > static inline bool cpu_supports_mixed_endian_el0(void) > { > diff --git a/arch/arm64/include/asm/kvm_cpufeature.h b/arch/arm64/include/asm/kvm_cpufeature.h > new file mode 100644 > index 000000000000..d34f85cba358 > --- /dev/null > +++ b/arch/arm64/include/asm/kvm_cpufeature.h > @@ -0,0 +1,17 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Copyright (C) 2020 - Google LLC > + * Author: Quentin Perret > + */ > + > +#include > + > +#ifndef KVM_HYP_CPU_FTR_REG > +#if defined(__KVM_NVHE_HYPERVISOR__) > +#define KVM_HYP_CPU_FTR_REG(id, name) extern struct arm64_ftr_reg name; > +#else > +#define KVM_HYP_CPU_FTR_REG(id, name) DECLARE_KVM_NVHE_SYM(name); > +#endif > +#endif > + > +KVM_HYP_CPU_FTR_REG(SYS_CTR_EL0, arm64_ftr_reg_ctrel0) > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 06ca4828005f..459ee557f87c 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -751,9 +751,13 @@ void kvm_clr_pmu_events(u32 clr); > > void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu); > void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu); > + > +void setup_kvm_el2_caps(void); > #else > static inline void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr) {} > static inline void kvm_clr_pmu_events(u32 clr) {} > + > +static inline void setup_kvm_el2_caps(void) {} > #endif > > void kvm_vcpu_load_sysregs_vhe(struct kvm_vcpu *vcpu); > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index 066030717a4c..f2d8b479ff74 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -1154,6 +1154,18 @@ u64 read_sanitised_ftr_reg(u32 id) > } > EXPORT_SYMBOL_GPL(read_sanitised_ftr_reg); > > +int copy_ftr_reg(u32 id, struct arm64_ftr_reg *dst) > +{ > + struct arm64_ftr_reg *regp = get_arm64_ftr_reg(id); > + > + if (!regp) > + return -EINVAL; > + > + memcpy(dst, regp, sizeof(*regp)); Can you not just use struct assignment here? > diff --git a/arch/arm64/kvm/hyp/nvhe/cache.S b/arch/arm64/kvm/hyp/nvhe/cache.S > new file mode 100644 > index 000000000000..36cef6915428 > --- /dev/null > +++ b/arch/arm64/kvm/hyp/nvhe/cache.S > @@ -0,0 +1,13 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Code copied from arch/arm64/mm/cache.S. > + */ > + > +#include > +#include > +#include > + > +SYM_FUNC_START_PI(__flush_dcache_area) > + dcache_by_line_op civac, sy, x0, x1, x2, x3 > + ret > +SYM_FUNC_END_PI(__flush_dcache_area) Separate patch for this? (or fold it into that one really near the start that introduces some other PI helpers). > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index 4f2f1e3145de..84be93df52fa 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -2775,3 +2776,23 @@ void kvm_sys_reg_table_init(void) > /* Clear all higher bits. */ > cache_levels &= (1 << (i*3))-1; > } > + > +#undef KVM_HYP_CPU_FTR_REG > +#define KVM_HYP_CPU_FTR_REG(id, name) \ > + { .sys_id = id, .dst = (struct arm64_ftr_reg *)&kvm_nvhe_sym(name) }, > +struct __ftr_reg_copy_entry { > + u32 sys_id; > + struct arm64_ftr_reg *dst; > +} hyp_ftr_regs[] __initdata = { > + #include > +}; This looks a bit elaborate to me. Why can't you just spell things out here like: #define KVM_HYP_CPU_FTR_REG(id, name) \ { .sys_id = id, .dst = (struct arm64_ftr_reg *)&kvm_nvhe_sym(name) } struct __ftr_reg_copy_entry { u32 sys_id; struct arm64_ftr_reg *dst; } hyp_ftr_regs[] __initdata = { KVM_HYP_CPU_FTR_REG(SYS_CTR_EL0, arm64_ftr_reg_ctrel0), ... }; and then have the header file be a normal, guarded header which just declares these things? The id parameter to the macro isn't used there. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel