diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index 78813b8fad32..6c2a35da867e 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -188,23 +188,30 @@ int kvm_arm_coproc_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *); int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, int exception_index); -static inline void __cpu_init_hyp_mode(unsigned long long pgd_ptr, +static inline void __cpu_init_hyp_mode(unsigned long long boot_pgd_ptr, + unsigned long long pgd_ptr, unsigned long hyp_stack_ptr, unsigned long vector_ptr) { - unsigned long pgd_low, pgd_high; - - pgd_low = (pgd_ptr & ((1ULL << 32) - 1)); - pgd_high = (pgd_ptr >> 32ULL); - /* - * Call initialization code, and switch to the full blown - * HYP code. The init code doesn't need to preserve these registers as - * r1-r3 and r12 are already callee save according to the AAPCS. - * Note that we slightly misuse the prototype by casing the pgd_low to - * a void *. + * Call initialization code, and switch to the full blown HYP + * code. The init code doesn't need to preserve these + * registers as r0-r3 are already callee saved according to + * the AAPCS. + * Note that we slightly misuse the prototype by casing the + * stack pointer to a void *. + * + * We don't have enough registers to perform the full init in + * one go. Install the boot PGD first, and then install the + * runtime PGD, stack pointer and vectors. The PGDs are always + * passed as the third argument, in order to be passed into + * r2-r3 to the init code (yes, this is compliant with the + * PCS!). */ - kvm_call_hyp((void *)pgd_low, pgd_high, hyp_stack_ptr, vector_ptr); + + kvm_call_hyp(NULL, 0, boot_pgd_ptr); + + kvm_call_hyp((void*)hyp_stack_ptr, vector_ptr, pgd_ptr); } int kvm_perf_init(void); diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h index 92eb20d57942..24b767a8cdb9 100644 --- a/arch/arm/include/asm/kvm_mmu.h +++ b/arch/arm/include/asm/kvm_mmu.h @@ -19,17 +19,29 @@ #ifndef __ARM_KVM_MMU_H__ #define __ARM_KVM_MMU_H__ -#include -#include +#include +#include /* * We directly use the kernel VA for the HYP, as we can directly share * the mapping (HTTBR "covers" TTBR1). */ -#define HYP_PAGE_OFFSET_MASK (~0UL) +#define HYP_PAGE_OFFSET_MASK UL(~0) #define HYP_PAGE_OFFSET PAGE_OFFSET #define KERN_TO_HYP(kva) (kva) +/* + * Our virtual mapping for the boot-time MMU-enable code. Must be + * shared across all the page-tables. Conveniently, we use the vectors + * page, where no kernel data will ever be shared with HYP. + */ +#define TRAMPOLINE_VA UL(CONFIG_VECTORS_BASE) + +#ifndef __ASSEMBLY__ + +#include +#include + int create_hyp_mappings(void *from, void *to); int create_hyp_io_mappings(void *from, void *to, phys_addr_t); void free_hyp_pgds(void); @@ -44,6 +56,8 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run); void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu); phys_addr_t kvm_mmu_get_httbr(void); +phys_addr_t kvm_mmu_get_boot_httbr(void); +phys_addr_t kvm_get_idmap_vector(void); int kvm_mmu_init(void); void kvm_clear_hyp_idmap(void); @@ -113,4 +127,8 @@ static inline void coherent_icache_guest_page(struct kvm *kvm, gfn_t gfn) } } +#define kvm_flush_dcache_to_poc(a,l) __cpuc_flush_dcache_area((a), (l)) + +#endif /* !__ASSEMBLY__ */ + #endif /* __ARM_KVM_MMU_H__ */ diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 16f164a5db86..fc47bd721ab0 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -787,20 +787,22 @@ long kvm_arch_vm_ioctl(struct file *filp, static void cpu_init_hyp_mode(void *vector) { + unsigned long long boot_pgd_ptr; unsigned long long pgd_ptr; unsigned long hyp_stack_ptr; unsigned long stack_page; unsigned long vector_ptr; /* Switch from the HYP stub to our own HYP init vector */ - __hyp_set_vectors((unsigned long)vector); + __hyp_set_vectors(kvm_get_idmap_vector()); + boot_pgd_ptr = (unsigned long long)kvm_mmu_get_boot_httbr(); pgd_ptr = (unsigned long long)kvm_mmu_get_httbr(); stack_page = __get_cpu_var(kvm_arm_hyp_stack_page); hyp_stack_ptr = stack_page + PAGE_SIZE; vector_ptr = (unsigned long)__kvm_hyp_vector; - __cpu_init_hyp_mode(pgd_ptr, hyp_stack_ptr, vector_ptr); + __cpu_init_hyp_mode(boot_pgd_ptr, pgd_ptr, hyp_stack_ptr, vector_ptr); } /** @@ -853,11 +855,6 @@ static int init_hyp_mode(void) (void *)(long)init_phys_addr, 1); } - /* - * Unmap the identity mapping - */ - kvm_clear_hyp_idmap(); - /* * Map the Hyp-code called directly from the host */ diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S index 9f37a79b880b..f048338135f7 100644 --- a/arch/arm/kvm/init.S +++ b/arch/arm/kvm/init.S @@ -21,13 +21,33 @@ #include #include #include +#include /******************************************************************** * Hypervisor initialization * - should be called with: - * r0,r1 = Hypervisor pgd pointer - * r2 = top of Hyp stack (kernel VA) - * r3 = pointer to hyp vectors + * r0 = top of Hyp stack (kernel VA) + * r1 = pointer to hyp vectors + * r2,r3 = Hypervisor pgd pointer + * + * The init scenario is: + * - We jump in HYP with four parameters: boot HYP pgd, runtime HYP pgd, + * runtime stack, runtime vectors + * - Enable the MMU with the boot pgd + * - Jump to a target into the trampoline page (remember, this is the same + * physical page!) + * - Now switch to the runtime pgd (same VA, and still the same physical + * page!) + * - Invalidate TLBs + * - Set stack and vectors + * - Profit! (or eret, if you only care about the code). + * + * As we only have four registers available to pass parameters (and we + * need six), we split the init in two phases: + * - Phase 1: r0 = 0, r1 = 0, r2,r3 contain the boot PGD. + * Provides the basic HYP init, and enable the MMU. + * - Phase 2: r0 = ToS, r1 = vectors, r2,r3 contain the runtime PGD. + * Switches to the runtime PGD, set stack and vectors. */ .text @@ -47,22 +67,25 @@ __kvm_hyp_init: W(b) . __do_hyp_init: + cmp r0, #0 @ We have a SP? + bne phase2 @ Yes, second stage init + @ Set the HTTBR to point to the hypervisor PGD pointer passed - mcrr p15, 4, r0, r1, c2 + mcrr p15, 4, r2, r3, c2 @ Set the HTCR and VTCR to the same shareability and cacheability @ settings as the non-secure TTBCR and with T0SZ == 0. mrc p15, 4, r0, c2, c0, 2 @ HTCR - ldr r12, =HTCR_MASK - bic r0, r0, r12 + ldr r2, =HTCR_MASK + bic r0, r0, r2 mrc p15, 0, r1, c2, c0, 2 @ TTBCR and r1, r1, #(HTCR_MASK & ~TTBCR_T0SZ) orr r0, r0, r1 mcr p15, 4, r0, c2, c0, 2 @ HTCR mrc p15, 4, r1, c2, c1, 2 @ VTCR - ldr r12, =VTCR_MASK - bic r1, r1, r12 + ldr r2, =VTCR_MASK + bic r1, r1, r2 bic r0, r0, #(~VTCR_HTCR_SH) @ clear non-reusable HTCR bits orr r1, r0, r1 orr r1, r1, #(KVM_VTCR_SL0 | KVM_VTCR_T0SZ | KVM_VTCR_S) @@ -85,24 +108,41 @@ __do_hyp_init: @ - Memory alignment checks: enabled @ - MMU: enabled (this code must be run from an identity mapping) mrc p15, 4, r0, c1, c0, 0 @ HSCR - ldr r12, =HSCTLR_MASK - bic r0, r0, r12 + ldr r2, =HSCTLR_MASK + bic r0, r0, r2 mrc p15, 0, r1, c1, c0, 0 @ SCTLR - ldr r12, =(HSCTLR_EE | HSCTLR_FI | HSCTLR_I | HSCTLR_C) - and r1, r1, r12 - ARM( ldr r12, =(HSCTLR_M | HSCTLR_A) ) - THUMB( ldr r12, =(HSCTLR_M | HSCTLR_A | HSCTLR_TE) ) - orr r1, r1, r12 + ldr r2, =(HSCTLR_EE | HSCTLR_FI | HSCTLR_I | HSCTLR_C) + and r1, r1, r2 + ARM( ldr r2, =(HSCTLR_M | HSCTLR_A) ) + THUMB( ldr r2, =(HSCTLR_M | HSCTLR_A | HSCTLR_TE) ) + orr r1, r1, r2 orr r0, r0, r1 isb mcr p15, 4, r0, c1, c0, 0 @ HSCR - isb - @ Set stack pointer and return to the kernel - mov sp, r2 + @ End of init phase-1 + eret + +phase2: + @ Set stack pointer + mov sp, r0 @ Set HVBAR to point to the HYP vectors - mcr p15, 4, r3, c12, c0, 0 @ HVBAR + mcr p15, 4, r1, c12, c0, 0 @ HVBAR + + @ Jump to the trampoline page + ldr r0, =TRAMPOLINE_VA + adr r1, target + bfi r0, r1, #0, #PAGE_SHIFT + mov pc, r0 + +target: @ We're now in the trampoline code, switch page tables + mcrr p15, 4, r2, r3, c2 + isb + + @ Invalidate the old TLBs + mcr p15, 4, r0, c8, c7, 0 @ TLBIALLH + dsb eret diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 7464824c17ef..4646c17f571c 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -32,9 +32,15 @@ extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[]; +static pgd_t *boot_hyp_pgd; static pgd_t *hyp_pgd; static DEFINE_MUTEX(kvm_hyp_pgd_mutex); +static void *init_bounce_page; +static unsigned long hyp_idmap_start; +static unsigned long hyp_idmap_end; +static phys_addr_t hyp_idmap_vector; + static void kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa) { kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, kvm, ipa); @@ -152,9 +158,12 @@ static void unmap_range(pgd_t *pgdp, unsigned long long start, u64 size) /** * free_hyp_pgds - free Hyp-mode page tables * - * Assumes hyp_pgd is a page table used strictly in Hyp-mode and therefore contains - * either mappings in the kernel memory area (above PAGE_OFFSET), or - * device mappings in the vmalloc range (from VMALLOC_START to VMALLOC_END). + * Assumes hyp_pgd is a page table used strictly in Hyp-mode and + * therefore contains either mappings in the kernel memory area (above + * PAGE_OFFSET), or device mappings in the vmalloc range (from + * VMALLOC_START to VMALLOC_END). + * + * boot_hyp_pgd should only map two pages for the init code. */ void free_hyp_pgds(void) { @@ -162,6 +171,12 @@ void free_hyp_pgds(void) mutex_lock(&kvm_hyp_pgd_mutex); + if (boot_hyp_pgd) { + unmap_range(boot_hyp_pgd, hyp_idmap_start, PAGE_SIZE); + unmap_range(boot_hyp_pgd, TRAMPOLINE_VA, PAGE_SIZE); + kfree(boot_hyp_pgd); + } + if (hyp_pgd) { for (addr = PAGE_OFFSET; virt_addr_valid(addr); addr += PGDIR_SIZE) unmap_range(hyp_pgd, KERN_TO_HYP(addr), PGDIR_SIZE); @@ -170,6 +185,7 @@ void free_hyp_pgds(void) kfree(hyp_pgd); } + kfree(init_bounce_page); mutex_unlock(&kvm_hyp_pgd_mutex); } @@ -185,6 +201,7 @@ static void create_hyp_pte_mappings(pmd_t *pmd, unsigned long start, pte = pte_offset_kernel(pmd, addr); kvm_set_pte(pte, pfn_pte(pfn, prot)); get_page(virt_to_page(pte)); + kvm_flush_dcache_to_poc(pte, sizeof(*pte)); pfn++; } while (addr += PAGE_SIZE, addr != end); } @@ -211,6 +228,7 @@ static int create_hyp_pmd_mappings(pud_t *pud, unsigned long start, } pmd_populate_kernel(NULL, pmd, pte); get_page(virt_to_page(pmd)); + kvm_flush_dcache_to_poc(pmd, sizeof(*pmd)); } next = pmd_addr_end(addr, end); @@ -248,6 +266,7 @@ static int __create_hyp_mappings(pgd_t *pgdp, } pud_populate(NULL, pud, pmd); get_page(virt_to_page(pud)); + kvm_flush_dcache_to_poc(pud, sizeof(*pud)); } next = pgd_addr_end(addr, end); @@ -689,18 +708,64 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu) phys_addr_t kvm_mmu_get_httbr(void) { - VM_BUG_ON(!virt_addr_valid(hyp_pgd)); return virt_to_phys(hyp_pgd); } +phys_addr_t kvm_mmu_get_boot_httbr(void) +{ + return virt_to_phys(boot_hyp_pgd); +} + +phys_addr_t kvm_get_idmap_vector(void) +{ + return hyp_idmap_vector; +} + int kvm_mmu_init(void) { - unsigned long hyp_idmap_start = virt_to_phys(__hyp_idmap_text_start); - unsigned long hyp_idmap_end = virt_to_phys(__hyp_idmap_text_end); int err; + hyp_idmap_start = virt_to_phys(__hyp_idmap_text_start); + hyp_idmap_end = virt_to_phys(__hyp_idmap_text_end); + hyp_idmap_vector = virt_to_phys(__kvm_hyp_init); + + if ((hyp_idmap_start ^ hyp_idmap_end) & PAGE_MASK) { + /* + * Our init code is crossing a page boundary. Allocate + * a bounce page, copy the code over and use that. + */ + size_t len = __hyp_idmap_text_end - __hyp_idmap_text_start; + phys_addr_t phys_base; + + init_bounce_page = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!init_bounce_page) { + kvm_err("Couldn't allocate HYP init bounce page\n"); + err = -ENOMEM; + goto out; + } + + memcpy(init_bounce_page, __hyp_idmap_text_start, len); + /* + * Warning: the code we just copied to the bounce page + * must be flushed to the point of coherency. + * Otherwise, the data may be sitting in L2, and HYP + * mode won't be able to observe it as it runs with + * caches off at that point. + */ + kvm_flush_dcache_to_poc(init_bounce_page, len); + + phys_base = virt_to_phys(init_bounce_page); + hyp_idmap_vector += phys_base - hyp_idmap_start; + hyp_idmap_start = phys_base; + hyp_idmap_end = phys_base + len; + + kvm_info("Using HYP init bounce page @%lx\n", + (unsigned long)phys_base); + } + hyp_pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL); - if (!hyp_pgd) { + boot_hyp_pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL); + if (!hyp_pgd || !boot_hyp_pgd) { kvm_err("Hyp mode PGD not allocated\n"); err = -ENOMEM; goto out; @@ -718,39 +783,30 @@ int kvm_mmu_init(void) goto out; } + /* Map the very same page at the trampoline VA */ + err = __create_hyp_mappings(boot_hyp_pgd, + TRAMPOLINE_VA, TRAMPOLINE_VA + PAGE_SIZE, + __phys_to_pfn(hyp_idmap_start), + PAGE_HYP); + if (err) { + kvm_err("Failed to map trampoline @%lx into boot HYP pgd\n", + TRAMPOLINE_VA); + goto out; + } + + /* Map the same page again into the runtime page tables */ + err = __create_hyp_mappings(hyp_pgd, + TRAMPOLINE_VA, TRAMPOLINE_VA + PAGE_SIZE, + __phys_to_pfn(hyp_idmap_start), + PAGE_HYP); + if (err) { + kvm_err("Failed to map trampoline @%lx into runtime HYP pgd\n", + TRAMPOLINE_VA); + goto out; + } + return 0; out: free_hyp_pgds(); return err; } - -/** - * kvm_clear_idmap - remove all idmaps from the hyp pgd - * - * Free the underlying pmds for all pgds in range and clear the pgds (but - * don't free them) afterwards. - */ -void kvm_clear_hyp_idmap(void) -{ - unsigned long addr, end; - unsigned long next; - pgd_t *pgd = hyp_pgd; - pud_t *pud; - pmd_t *pmd; - - addr = virt_to_phys(__hyp_idmap_text_start); - end = virt_to_phys(__hyp_idmap_text_end); - - pgd += pgd_index(addr); - do { - next = pgd_addr_end(addr, end); - if (pgd_none_or_clear_bad(pgd)) - continue; - pud = pud_offset(pgd, addr); - pmd = pmd_offset(pud, addr); - - pud_clear(pud); - kvm_clean_pmd_entry(pmd); - pmd_free(NULL, (pmd_t *)((unsigned long)pmd & PAGE_MASK)); - } while (pgd++, addr = next, addr < end); -}