From: Marc Zyngier <maz@kernel.org>
To: Quentin Perret <qperret@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
devicetree@vger.kernel.org, android-kvm@google.com,
linux-kernel@vger.kernel.org, kernel-team@android.com,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org,
Fuad Tabba <tabba@google.com>,
Mark Rutland <mark.rutland@arm.com>,
David Brazdil <dbrazdil@google.com>
Subject: Re: [RFC PATCH v2 13/26] KVM: arm64: Enable access to sanitized CPU features at EL2
Date: Wed, 13 Jan 2021 11:33:13 +0000 [thread overview]
Message-ID: <d55643ea391f73a2297f499f3219ba8a@kernel.org> (raw)
In-Reply-To: <20210108121524.656872-14-qperret@google.com>
Hi Quentin,
On 2021-01-08 12:15, 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
> <asm/kvm_cpufeature.h> 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 <qperret@google.com>
> ---
> arch/arm64/include/asm/cpufeature.h | 1 +
> arch/arm64/include/asm/kvm_cpufeature.h | 17 ++++++++++++++
> arch/arm64/kernel/cpufeature.c | 12 ++++++++++
> arch/arm64/kvm/arm.c | 31 +++++++++++++++++++++++++
> arch/arm64/kvm/hyp/nvhe/Makefile | 3 ++-
> arch/arm64/kvm/hyp/nvhe/cache.S | 13 +++++++++++
> arch/arm64/kvm/hyp/nvhe/cpufeature.c | 8 +++++++
> 7 files changed, 84 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 16063c813dcd..742e9bcc051b 100644
> --- a/arch/arm64/include/asm/cpufeature.h
> +++ b/arch/arm64/include/asm/cpufeature.h
> @@ -600,6 +600,7 @@ void __init setup_cpu_features(void);
> void check_local_cpu_capabilities(void);
>
> u64 read_sanitised_ftr_reg(u32 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 <qperret@google.com>
> + */
> +
> +#include <asm/cpufeature.h>
> +
> +#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/kernel/cpufeature.c
> b/arch/arm64/kernel/cpufeature.c
> index bc3549663957..c2019aaaadc3 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -1113,6 +1113,18 @@ 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));
> +
> + return 0;
> +}
> +
> #define read_sysreg_case(r) \
> case r: return read_sysreg_s(r)
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 51b53ca36dc5..9fd769349e9e 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -34,6 +34,7 @@
> #include <asm/virt.h>
> #include <asm/kvm_arm.h>
> #include <asm/kvm_asm.h>
> +#include <asm/kvm_cpufeature.h>
> #include <asm/kvm_mmu.h>
> #include <asm/kvm_emulate.h>
> #include <asm/sections.h>
> @@ -1697,6 +1698,29 @@ static void teardown_hyp_mode(void)
> }
> }
>
> +#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) },
> +static const struct __ftr_reg_copy_entry {
> + u32 sys_id;
> + struct arm64_ftr_reg *dst;
Why do we need the whole data structure? Can't we just live with
sys_val?
> +} hyp_ftr_regs[] = {
> + #include <asm/kvm_cpufeature.h>
> +};
Can't this be made __initdata?
> +
> +static int copy_cpu_ftr_regs(void)
> +{
> + int i, ret;
> +
> + for (i = 0; i < ARRAY_SIZE(hyp_ftr_regs); i++) {
> + ret = copy_ftr_reg(hyp_ftr_regs[i].sys_id, hyp_ftr_regs[i].dst);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> /**
> * Inits Hyp-mode on all online CPUs
> */
> @@ -1705,6 +1729,13 @@ static int init_hyp_mode(void)
> int cpu;
> int err = 0;
>
> + /*
> + * Copy the required CPU feature register in their EL2 counterpart
> + */
> + err = copy_cpu_ftr_regs();
> + if (err)
> + return err;
> +
Just to keep things together, please move any sysreg manipulation into
sys_regs.c, most probably into kvm_sys_reg_table_init().
Thanks,
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2021-01-13 11:33 UTC|newest]
Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-08 12:14 [RFC PATCH v2 00/26] KVM/arm64: A stage 2 for the host Quentin Perret
2021-01-08 12:14 ` [RFC PATCH v2 01/26] arm64: lib: Annotate {clear,copy}_page() as position-independent Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 02/26] KVM: arm64: Link position-independent string routines into .hyp.text Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 03/26] arm64: kvm: Add standalone ticket spinlock implementation for use at hyp Quentin Perret
2021-02-01 17:28 ` Will Deacon
2021-02-01 17:40 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 04/26] KVM: arm64: Initialize kvm_nvhe_init_params early Quentin Perret
2021-02-01 17:41 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 05/26] KVM: arm64: Avoid free_page() in page-table allocator Quentin Perret
2021-02-01 17:46 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 06/26] KVM: arm64: Factor memory allocation out of pgtable.c Quentin Perret
2021-02-01 18:16 ` Will Deacon
2021-02-01 18:32 ` Quentin Perret
2021-02-01 18:39 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 07/26] KVM: arm64: Introduce a BSS section for use at Hyp Quentin Perret
2021-02-01 18:32 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 08/26] KVM: arm64: Make kvm_call_hyp() a function call " Quentin Perret
2021-02-01 18:41 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 09/26] KVM: arm64: Allow using kvm_nvhe_sym() in hyp code Quentin Perret
2021-02-01 18:43 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 10/26] KVM: arm64: Introduce an early Hyp page allocator Quentin Perret
2021-02-01 19:00 ` Will Deacon
2021-02-02 9:44 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 11/26] KVM: arm64: Stub CONFIG_DEBUG_LIST at Hyp Quentin Perret
2021-02-01 19:06 ` Will Deacon
2021-02-02 9:57 ` Quentin Perret
2021-02-02 10:00 ` Will Deacon
2021-02-02 10:14 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 12/26] KVM: arm64: Introduce a Hyp buddy page allocator Quentin Perret
2021-02-02 18:13 ` Will Deacon
2021-02-03 18:33 ` Quentin Perret
2021-02-04 14:31 ` Will Deacon
2021-02-04 14:52 ` Quentin Perret
2021-02-04 17:48 ` Will Deacon
2021-02-04 18:01 ` Quentin Perret
2021-02-04 18:13 ` Will Deacon
2021-02-04 18:24 ` Quentin Perret
2021-02-04 18:19 ` Quentin Perret
2021-02-04 18:24 ` Will Deacon
2021-02-04 18:32 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 13/26] KVM: arm64: Enable access to sanitized CPU features at EL2 Quentin Perret
2021-01-13 11:33 ` Marc Zyngier [this message]
2021-01-13 14:23 ` Quentin Perret
2021-01-13 14:35 ` Quentin Perret
2021-01-13 17:27 ` Marc Zyngier
2021-01-13 18:28 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 14/26] KVM: arm64: Factor out vector address calculation Quentin Perret
2021-02-02 18:24 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 15/26] of/fdt: Introduce early_init_dt_add_memory_hyp() Quentin Perret
2021-01-11 14:45 ` Rob Herring
2021-01-12 9:51 ` Quentin Perret
2021-01-12 14:10 ` Rob Herring
2021-01-12 14:26 ` Quentin Perret
2021-01-12 15:53 ` Rob Herring
2021-01-12 16:15 ` Quentin Perret
2021-01-12 16:45 ` Rob Herring
2021-01-12 16:50 ` Quentin Perret
2021-01-15 11:49 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 16/26] KVM: arm64: Prepare Hyp memory protection Quentin Perret
2021-02-03 14:37 ` Will Deacon
2021-02-04 10:47 ` Quentin Perret
2021-02-05 17:56 ` Will Deacon
2021-02-09 10:00 ` Quentin Perret
2021-02-09 12:23 ` Will Deacon
2021-02-19 18:32 ` Sean Christopherson
2021-02-22 11:04 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 17/26] KVM: arm64: Elevate Hyp mappings creation at EL2 Quentin Perret
2021-02-03 15:31 ` Will Deacon
2021-02-04 11:08 ` Quentin Perret
2021-02-05 18:01 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 18/26] KVM: arm64: Use kvm_arch for stage 2 pgtable Quentin Perret
2021-02-03 15:34 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 19/26] KVM: arm64: Use kvm_arch in kvm_s2_mmu Quentin Perret
2021-02-03 15:38 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 20/26] KVM: arm64: Set host stage 2 using kvm_nvhe_init_params Quentin Perret
2021-02-03 16:05 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 21/26] KVM: arm64: Refactor kvm_arm_setup_stage2() Quentin Perret
2021-02-03 15:53 ` Will Deacon
2021-02-04 14:07 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 22/26] KVM: arm64: Refactor __load_guest_stage2() Quentin Perret
2021-02-03 15:54 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 23/26] KVM: arm64: Refactor __populate_fault_info() Quentin Perret
2021-02-03 15:58 ` Will Deacon
2021-02-04 14:18 ` Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 24/26] KVM: arm64: Make memcache anonymous in pgtable allocator Quentin Perret
2021-02-03 15:59 ` Will Deacon
2021-02-04 14:24 ` Quentin Perret
2021-02-04 14:36 ` Will Deacon
2021-01-08 12:15 ` [RFC PATCH v2 25/26] KVM: arm64: Reserve memory for host stage 2 Quentin Perret
2021-01-08 12:15 ` [RFC PATCH v2 26/26] KVM: arm64: Wrap the host with a " Quentin Perret
2021-02-03 16:11 ` Will Deacon
2021-02-04 14:26 ` Quentin Perret
2021-02-04 14:37 ` Will Deacon
2021-02-17 16:27 ` [RFC PATCH v2 00/26] KVM/arm64: A stage 2 for the host Mate Toth-Pal
2021-02-17 17:24 ` Quentin Perret
2021-02-19 17:54 ` Sean Christopherson
2021-02-19 17:57 ` Quentin Perret
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