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    Subject[PATCH v3 09/23] kvm: arm64: Move hyp-init params to a per-CPU struct
    Date
    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 three
    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 <dbrazdil@google.com>
    ---
    arch/arm64/include/asm/kvm_asm.h | 6 ++++++
    arch/arm64/include/asm/kvm_hyp.h | 2 +-
    arch/arm64/kernel/asm-offsets.c | 3 +++
    arch/arm64/kvm/arm.c | 23 +++++++++++++----------
    arch/arm64/kvm/hyp/nvhe/hyp-init.S | 16 +++++++---------
    arch/arm64/kvm/hyp/nvhe/hyp-main.c | 2 ++
    6 files changed, 32 insertions(+), 20 deletions(-)

    diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
    index 531f9d04eefd..1a7b91534a16 100644
    --- a/arch/arm64/include/asm/kvm_asm.h
    +++ b/arch/arm64/include/asm/kvm_asm.h
    @@ -148,6 +148,12 @@ extern void *__vhe_undefined_symbol;

    #endif

    +struct kvm_nvhe_init_params {
    + unsigned long tpidr_el2;
    + unsigned long stack_hyp_va;
    + phys_addr_t pgd_pa;
    +};
    +
    /* 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..cb25c15e3d8d 100644
    --- a/arch/arm64/include/asm/kvm_hyp.h
    +++ b/arch/arm64/include/asm/kvm_hyp.h
    @@ -14,6 +14,7 @@

    DECLARE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
    DECLARE_PER_CPU(unsigned long, kvm_hyp_vector);
    +DECLARE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);

    #define read_sysreg_elx(r,nvh,vh) \
    ({ \
    @@ -98,4 +99,3 @@ void __noreturn __hyp_do_panic(bool restore_host, u64 spsr, u64 elr, u64 par);
    #endif

    #endif /* __ARM64_KVM_HYP_H__ */
    -
    diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
    index 7d32fc959b1a..8d6272a01a00 100644
    --- a/arch/arm64/kernel/asm-offsets.c
    +++ b/arch/arm64/kernel/asm-offsets.c
    @@ -110,6 +110,9 @@ 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_TPIDR_EL2, offsetof(struct kvm_nvhe_init_params, tpidr_el2));
    + DEFINE(NVHE_INIT_STACK_HYP_VA, offsetof(struct kvm_nvhe_init_params, stack_hyp_va));
    + DEFINE(NVHE_INIT_PGD_PA, offsetof(struct kvm_nvhe_init_params, pgd_pa));
    #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 cd6e5dec203f..7b718c6c6c52 100644
    --- a/arch/arm64/kvm/arm.c
    +++ b/arch/arm64/kvm/arm.c
    @@ -49,6 +49,7 @@ 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);
    @@ -1353,9 +1354,7 @@ static int kvm_init_vector_slots(void)

    static void cpu_init_hyp_mode(void)
    {
    - phys_addr_t pgd_ptr;
    - unsigned long hyp_stack_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 */
    @@ -1366,12 +1365,17 @@ 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);
    + params->stack_hyp_va = kern_hyp_va(__this_cpu_read(kvm_arm_hyp_stack_page) + PAGE_SIZE);
    + params->pgd_pa = kvm_mmu_get_httbr();
    +
    + /*
    + * Flush the init params from the data cache because the struct will
    + * be read while the MMU is off.
    + */
    + kvm_flush_dcache_to_poc(params, sizeof(*params));

    /*
    * Call initialization code, and switch to the full blown HYP code.
    @@ -1380,8 +1384,7 @@ 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, &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 b3492a3c4232..77c983aa90fa 100644
    --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
    +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
    @@ -47,9 +47,7 @@ __invalid:

    /*
    * x0: SMCCC function ID
    - * x1: HYP pgd
    - * x2: per-CPU offset
    - * x3: HYP stack
    + * x1: struct kvm_nvhe_init_params PA
    */
    __do_hyp_init:
    /* Check for a stub HVC call */
    @@ -70,10 +68,13 @@ __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_HYP_VA]
    + mov sp, x0
    +
    + ldr x1, [x1, #NVHE_INIT_PGD_PA]
    phys_to_ttbr x0, x1
    alternative_if ARM64_HAS_CNP
    orr x0, x0, #TTBR_CNP_BIT
    @@ -133,9 +134,6 @@ alternative_else_nop_endif
    msr sctlr_el2, x0
    isb

    - /* Set the stack */
    - mov sp, x3
    -
    /* Set the host vector */
    ldr x0, =__kvm_hyp_host_vector
    kimg_hyp_va x0, x1
    diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
    index 82df7fc24760..a4f1cac714d7 100644
    --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
    +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
    @@ -16,6 +16,8 @@
    #define DECLARE_REG(type, name, ctxt, reg) \
    type name = (type)cpu_reg(ctxt, (reg))

    +DEFINE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);
    +
    static void handle___kvm_vcpu_run(struct kvm_cpu_context *host_ctxt)
    {
    DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1);
    --
    2.29.2.454.gaff20da3a2-goog
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