| Message ID | 20201117181607.1761516-14-qperret@google.com |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC,01/27] arm64: lib: Annotate {clear,copy}_page() as position-independent | expand |
Hi Quentin, On Tue, Nov 17, 2020 at 6:16 PM 'Quentin Perret' via kernel-team <kernel-team@android.com> 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/kernel/image-vars.h | 2 ++ > 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 +++++++ > 8 files changed, 86 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 da250e4741bd..3dfbd76fb647 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> > + */ Missing include guard. > + > +#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 dd5bc0f0cf0d..3bc86d1423f8 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -1116,6 +1116,18 @@ 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/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h > index dd8ccc9efb6a..c35d768672eb 100644 > --- a/arch/arm64/kernel/image-vars.h > +++ b/arch/arm64/kernel/image-vars.h > @@ -116,6 +116,8 @@ __kvm_nvhe___memcpy = __kvm_nvhe___pi_memcpy; > __kvm_nvhe___memset = __kvm_nvhe___pi_memset; > #endif > > +_kvm_nvhe___flush_dcache_area = __kvm_nvhe___pi___flush_dcache_area; > + > #endif /* CONFIG_KVM */ > > #endif /* __ARM64_KERNEL_IMAGE_VARS_H */ > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index 391cf6753a13..c7f8fca97202 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> > @@ -1636,6 +1637,29 @@ 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; > +} hyp_ftr_regs[] = { > + #include <asm/kvm_cpufeature.h> > +}; > + > +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 > */ > @@ -1644,6 +1668,13 @@ 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; > + > /* > * Allocate Hyp PGD and setup Hyp identity mapping > */ > diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile > index 9e5eacfec6ec..72cfe53f106f 100644 > --- a/arch/arm64/kvm/hyp/nvhe/Makefile > +++ b/arch/arm64/kvm/hyp/nvhe/Makefile > @@ -10,7 +10,8 @@ lib-objs := clear_page.o copy_page.o memcpy.o memset.o > lib-objs := $(addprefix ../../../lib/, $(lib-objs)) > > obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \ > - hyp-main.o hyp-smp.o psci-relay.o early_alloc.o stub.o page_alloc.o > + hyp-main.o hyp-smp.o psci-relay.o early_alloc.o stub.o page_alloc.o \ > + cache.o cpufeature.o > obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \ > ../fpsimd.o ../hyp-entry.o ../exception.o > obj-y += $(lib-objs) > 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 <linux/linkage.h> > +#include <asm/assembler.h> > +#include <asm/alternative.h> > + > +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) > diff --git a/arch/arm64/kvm/hyp/nvhe/cpufeature.c b/arch/arm64/kvm/hyp/nvhe/cpufeature.c > new file mode 100644 > index 000000000000..a887508f996f > --- /dev/null > +++ b/arch/arm64/kvm/hyp/nvhe/cpufeature.c > @@ -0,0 +1,8 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (C) 2020 - Google LLC > + * Author: Quentin Perret <qperret@google.com> > + */ > + > +#define KVM_HYP_CPU_FTR_REG(id, name) struct arm64_ftr_reg name; > +#include <asm/kvm_cpufeature.h> > -- > 2.29.2.299.gdc1121823c-goog > > -- > To unsubscribe from this group and stop receiving emails from it, send an email to kernel-team+unsubscribe@android.com. > /fuad
> +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/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h > index dd8ccc9efb6a..c35d768672eb 100644 > --- a/arch/arm64/kernel/image-vars.h > +++ b/arch/arm64/kernel/image-vars.h > @@ -116,6 +116,8 @@ __kvm_nvhe___memcpy = __kvm_nvhe___pi_memcpy; > __kvm_nvhe___memset = __kvm_nvhe___pi_memset; > #endif > > +_kvm_nvhe___flush_dcache_area = __kvm_nvhe___pi___flush_dcache_area; > + Could you help my understand why we need this? * Why do we need PI routines in the first place? Would my series that fixes relocations in hyp code remove the need? * You added these aliases for the string routines because you were worried somebody would change the implementation in arch/arm64/lib, right? But this cache flush function is defined in hyp/nvhe. So why do we need to point to the PI alias if we control the implementation?
On Monday 23 Nov 2020 at 10:55:20 (+0000), Fuad Tabba wrote: > > 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> > > + */ > > Missing include guard. Right, but on purpose :) See how arm.c includes this header twice with different definitions of KVM_HYP_CPU_FTR_REG for instance. Thanks, Quentin
On Monday 23 Nov 2020 at 13:22:23 (+0000), David Brazdil wrote: > Could you help my understand why we need this? > * Why do we need PI routines in the first place? Would my series that fixes > relocations in hyp code remove the need? > * You added these aliases for the string routines because you were worried > somebody would change the implementation in arch/arm64/lib, right? But this > cache flush function is defined in hyp/nvhe. So why do we need to point to > the PI alias if we control the implementation? Right, in the specific case of the __flush_dcache_area() function none of the PI stuff is really needed I think. I did it this way to keep things as consistent as possible with the host-side implementation, but that is not required. I understand this can cause confusion, so yes, I'll simplify this for v2. Cheers, Quentin
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index da250e4741bd..3dfbd76fb647 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 dd5bc0f0cf0d..3bc86d1423f8 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1116,6 +1116,18 @@ 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/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h index dd8ccc9efb6a..c35d768672eb 100644 --- a/arch/arm64/kernel/image-vars.h +++ b/arch/arm64/kernel/image-vars.h @@ -116,6 +116,8 @@ __kvm_nvhe___memcpy = __kvm_nvhe___pi_memcpy; __kvm_nvhe___memset = __kvm_nvhe___pi_memset; #endif +_kvm_nvhe___flush_dcache_area = __kvm_nvhe___pi___flush_dcache_area; + #endif /* CONFIG_KVM */ #endif /* __ARM64_KERNEL_IMAGE_VARS_H */ diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 391cf6753a13..c7f8fca97202 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> @@ -1636,6 +1637,29 @@ 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; +} hyp_ftr_regs[] = { + #include <asm/kvm_cpufeature.h> +}; + +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 */ @@ -1644,6 +1668,13 @@ 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; + /* * Allocate Hyp PGD and setup Hyp identity mapping */ diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile index 9e5eacfec6ec..72cfe53f106f 100644 --- a/arch/arm64/kvm/hyp/nvhe/Makefile +++ b/arch/arm64/kvm/hyp/nvhe/Makefile @@ -10,7 +10,8 @@ lib-objs := clear_page.o copy_page.o memcpy.o memset.o lib-objs := $(addprefix ../../../lib/, $(lib-objs)) obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \ - hyp-main.o hyp-smp.o psci-relay.o early_alloc.o stub.o page_alloc.o + hyp-main.o hyp-smp.o psci-relay.o early_alloc.o stub.o page_alloc.o \ + cache.o cpufeature.o obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \ ../fpsimd.o ../hyp-entry.o ../exception.o obj-y += $(lib-objs) 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 <linux/linkage.h> +#include <asm/assembler.h> +#include <asm/alternative.h> + +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) diff --git a/arch/arm64/kvm/hyp/nvhe/cpufeature.c b/arch/arm64/kvm/hyp/nvhe/cpufeature.c new file mode 100644 index 000000000000..a887508f996f --- /dev/null +++ b/arch/arm64/kvm/hyp/nvhe/cpufeature.c @@ -0,0 +1,8 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2020 - Google LLC + * Author: Quentin Perret <qperret@google.com> + */ + +#define KVM_HYP_CPU_FTR_REG(id, name) struct arm64_ftr_reg name; +#include <asm/kvm_cpufeature.h>
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/kernel/image-vars.h | 2 ++ 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 +++++++ 8 files changed, 86 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