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Tue, 10 Nov 2020 15:30:22 +0000 MIME-Version: 1.0 Date: Tue, 10 Nov 2020 15:30:22 +0000 From: Marc Zyngier To: David Brazdil Subject: Re: [PATCH v1 08/24] kvm: arm64: Move hyp-init params to a per-CPU struct In-Reply-To: <20201109113233.9012-9-dbrazdil@google.com> References: <20201109113233.9012-1-dbrazdil@google.com> <20201109113233.9012-9-dbrazdil@google.com> User-Agent: Roundcube Webmail/1.4.9 Message-ID: X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: dbrazdil@google.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org, dennis@kernel.org, tj@kernel.org, cl@linux.com, mark.rutland@arm.com, lorenzo.pieralisi@arm.com, qperret@google.com, ascull@google.com, qwandor@google.com, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201110_103026_363723_3E4C2121 X-CRM114-Status: GOOD ( 29.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , kernel-team@android.com, Lorenzo Pieralisi , Andrew Walbran , Suzuki K Poulose , Catalin Marinas , Quentin Perret , linux-kernel@vger.kernel.org, James Morse , linux-arm-kernel@lists.infradead.org, Tejun Heo , Dennis Zhou , Christoph Lameter , Will Deacon , kvmarm@lists.cs.columbia.edu, Julien Thierry , Andrew Scull Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2020-11-09 11:32, David Brazdil wrote: > Once we start initializing KVM on newly booted cores before the rest of > the kernel, parameters to __do_hyp_init will need to be provided by EL2 > rather than EL1. At that point it will not be possible to pass its four > arguments directly because PSCI_CPU_ON only supports one context > argument. > > Refactor __do_hyp_init to accept its parameters in a struct. This > prepares the code for KVM booting cores as well as removes any limits > on > the number of __do_hyp_init arguments. > > Signed-off-by: David Brazdil > --- > arch/arm64/include/asm/kvm_asm.h | 7 +++++++ > arch/arm64/include/asm/kvm_hyp.h | 4 ++++ > arch/arm64/kernel/asm-offsets.c | 4 ++++ > arch/arm64/kvm/arm.c | 26 ++++++++++++++------------ > arch/arm64/kvm/hyp/nvhe/hyp-init.S | 21 ++++++++++----------- > arch/arm64/kvm/hyp/nvhe/hyp-main.c | 2 ++ > 6 files changed, 41 insertions(+), 23 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_asm.h > b/arch/arm64/include/asm/kvm_asm.h > index 54387ccd1ab2..a49a87a186c3 100644 > --- a/arch/arm64/include/asm/kvm_asm.h > +++ b/arch/arm64/include/asm/kvm_asm.h > @@ -150,6 +150,13 @@ extern void *__vhe_undefined_symbol; > > #endif > > +struct kvm_nvhe_init_params { > + phys_addr_t pgd_ptr; > + unsigned long tpidr_el2; > + unsigned long hyp_stack_ptr; > + unsigned long vector_ptr; > +}; Please add some documentation here, specially indicating what address space the values are relative to. > + > /* Translate a kernel address @ptr into its equivalent linear mapping > */ > #define kvm_ksym_ref(ptr) \ > ({ \ > diff --git a/arch/arm64/include/asm/kvm_hyp.h > b/arch/arm64/include/asm/kvm_hyp.h > index 6b664de5ec1f..a3289071f3d8 100644 > --- a/arch/arm64/include/asm/kvm_hyp.h > +++ b/arch/arm64/include/asm/kvm_hyp.h > @@ -15,6 +15,10 @@ > DECLARE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt); > DECLARE_PER_CPU(unsigned long, kvm_hyp_vector); > > +#ifdef __KVM_NVHE_HYPERVISOR__ > +DECLARE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params); > +#endif > + > #define read_sysreg_elx(r,nvh,vh) \ > ({ \ > u64 reg; \ > diff --git a/arch/arm64/kernel/asm-offsets.c > b/arch/arm64/kernel/asm-offsets.c > index 7d32fc959b1a..0cbb86135c7c 100644 > --- a/arch/arm64/kernel/asm-offsets.c > +++ b/arch/arm64/kernel/asm-offsets.c > @@ -110,6 +110,10 @@ int main(void) > DEFINE(CPU_APGAKEYLO_EL1, offsetof(struct kvm_cpu_context, > sys_regs[APGAKEYLO_EL1])); > DEFINE(HOST_CONTEXT_VCPU, offsetof(struct kvm_cpu_context, > __hyp_running_vcpu)); > DEFINE(HOST_DATA_CONTEXT, offsetof(struct kvm_host_data, > host_ctxt)); > + DEFINE(NVHE_INIT_PGD_PTR, offsetof(struct kvm_nvhe_init_params, > pgd_ptr)); > + DEFINE(NVHE_INIT_TPIDR_EL2, offsetof(struct kvm_nvhe_init_params, > tpidr_el2)); > + DEFINE(NVHE_INIT_STACK_PTR, offsetof(struct kvm_nvhe_init_params, > hyp_stack_ptr)); > + DEFINE(NVHE_INIT_VECTOR_PTR, offsetof(struct kvm_nvhe_init_params, > vector_ptr)); > #endif > #ifdef CONFIG_CPU_PM > DEFINE(CPU_CTX_SP, offsetof(struct cpu_suspend_ctx, sp)); > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index b85b4294b72d..1a57b6025937 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -50,6 +50,7 @@ DECLARE_KVM_HYP_PER_CPU(unsigned long, > kvm_hyp_vector); > > static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page); > unsigned long kvm_arm_hyp_percpu_base[NR_CPUS]; > +DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_init_params, > kvm_init_params); > > /* The VMID used in the VTTBR */ > static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1); > @@ -1331,10 +1332,7 @@ static int kvm_map_vectors(void) > > static void cpu_init_hyp_mode(void) > { > - phys_addr_t pgd_ptr; > - unsigned long hyp_stack_ptr; > - unsigned long vector_ptr; > - unsigned long tpidr_el2; > + struct kvm_nvhe_init_params *params = > this_cpu_ptr_nvhe_sym(kvm_init_params); > struct arm_smccc_res res; > > /* Switch from the HYP stub to our own HYP init vector */ > @@ -1345,13 +1343,18 @@ static void cpu_init_hyp_mode(void) > * kernel's mapping to the linear mapping, and store it in tpidr_el2 > * so that we can use adr_l to access per-cpu variables in EL2. > */ > - tpidr_el2 = (unsigned long)this_cpu_ptr_nvhe_sym(__per_cpu_start) - > - (unsigned long)kvm_ksym_ref(CHOOSE_NVHE_SYM(__per_cpu_start)); > + params->tpidr_el2 = (unsigned > long)this_cpu_ptr_nvhe_sym(__per_cpu_start) - > + (unsigned long)kvm_ksym_ref(CHOOSE_NVHE_SYM(__per_cpu_start)); > > - pgd_ptr = kvm_mmu_get_httbr(); > - hyp_stack_ptr = __this_cpu_read(kvm_arm_hyp_stack_page) + PAGE_SIZE; > - hyp_stack_ptr = kern_hyp_va(hyp_stack_ptr); > - vector_ptr = (unsigned > long)kern_hyp_va(kvm_ksym_ref(__kvm_hyp_host_vector)); > + params->pgd_ptr = kvm_mmu_get_httbr(); > + params->vector_ptr = (unsigned > long)kern_hyp_va(kvm_ksym_ref(__kvm_hyp_host_vector)); > + params->hyp_stack_ptr = > kern_hyp_va(__this_cpu_read(kvm_arm_hyp_stack_page) + PAGE_SIZE); > + > + /* > + * Flush the init params from the data cache because the struct will > + * be read from while the MMU is off. s/from while/while/ ? > + */ > + __flush_dcache_area(params, sizeof(*params)); > > /* > * Call initialization code, and switch to the full blown HYP code. > @@ -1360,8 +1363,7 @@ static void cpu_init_hyp_mode(void) > * cpus_have_const_cap() wrapper. > */ > BUG_ON(!system_capabilities_finalized()); > - arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(__kvm_hyp_init), > - pgd_ptr, tpidr_el2, hyp_stack_ptr, vector_ptr, &res); > + arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(__kvm_hyp_init), > virt_to_phys(params), &res); > WARN_ON(res.a0 != SMCCC_RET_SUCCESS); > > /* > diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S > b/arch/arm64/kvm/hyp/nvhe/hyp-init.S > index 96e70f976ff5..6f3ac5d428ec 100644 > --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S > +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S > @@ -47,10 +47,7 @@ __invalid: > > /* > * x0: SMCCC function ID > - * x1: HYP pgd > - * x2: per-CPU offset > - * x3: HYP stack > - * x4: HYP vectors > + * x1: struct kvm_nvhe_init_params PA > */ > __do_hyp_init: > /* Check for a stub HVC call */ > @@ -71,10 +68,16 @@ __do_hyp_init: > mov x0, #SMCCC_RET_NOT_SUPPORTED > eret > > -1: > - /* Set tpidr_el2 for use by HYP to free a register */ > - msr tpidr_el2, x2 > +1: ldr x0, [x1, #NVHE_INIT_TPIDR_EL2] > + msr tpidr_el2, x0 > > + ldr x0, [x1, #NVHE_INIT_STACK_PTR] > + mov sp, x0 > + > + ldr x0, [x1, #NVHE_INIT_VECTOR_PTR] > + msr vbar_el2, x0 > + > + ldr x1, [x1, #NVHE_INIT_PGD_PTR] > phys_to_ttbr x0, x1 > alternative_if ARM64_HAS_CNP > orr x0, x0, #TTBR_CNP_BIT > @@ -134,10 +137,6 @@ alternative_else_nop_endif > msr sctlr_el2, x0 > isb > > - /* Set the stack and new vectors */ > - mov sp, x3 > - msr vbar_el2, x4 > - > /* Hello, World! */ > mov x0, #SMCCC_RET_SUCCESS > eret > diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c > b/arch/arm64/kvm/hyp/nvhe/hyp-main.c > index e2eafe2c93af..411b0f652417 100644 > --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c > +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c > @@ -14,6 +14,8 @@ > > #include > > +DEFINE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params); > + > static void handle_host_hcall(unsigned long func_id, > struct kvm_cpu_context *host_ctxt) > { Thanks, M. -- Jazz is not dead. 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