/*
* Copyright (C) 2012,2013 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ARM64_KVM_MMU_H__
#define __ARM64_KVM_MMU_H__
#include <asm/page.h>
#include <asm/memory.h>
#include <asm/cpufeature.h>
/*
* As ARMv8.0 only has the TTBR0_EL2 register, we cannot express
* "negative" addresses. This makes it impossible to directly share
* mappings with the kernel.
*
* Instead, give the HYP mode its own VA region at a fixed offset from
* the kernel by just masking the top bits (which are all ones for a
* kernel address). We need to find out how many bits to mask.
*
* We want to build a set of page tables that cover both parts of the
* idmap (the trampoline page used to initialize EL2), and our normal
* runtime VA space, at the same time.
*
* Given that the kernel uses VA_BITS for its entire address space,
* and that half of that space (VA_BITS - 1) is used for the linear
* mapping, we can also limit the EL2 space to (VA_BITS - 1).
*
* The main question is "Within the VA_BITS space, does EL2 use the
* top or the bottom half of that space to shadow the kernel's linear
* mapping?". As we need to idmap the trampoline page, this is
* determined by the range in which this page lives.
*
* If the page is in the bottom half, we have to use the top half. If
* the page is in the top half, we have to use the bottom half:
*
* T = __pa_symbol(__hyp_idmap_text_start)
* if (T & BIT(VA_BITS - 1))
* HYP_VA_MIN = 0 //idmap in upper half
* else
* HYP_VA_MIN = 1 << (VA_BITS - 1)
* HYP_VA_MAX = HYP_VA_MIN + (1 << (VA_BITS - 1)) - 1
*
* This of course assumes that the trampoline page exists within the
* VA_BITS range. If it doesn't, then it means we're in the odd case
* where the kernel idmap (as well as HYP) uses more levels than the
* kernel runtime page tables (as seen when the kernel is configured
* for 4k pages, 39bits VA, and yet memory lives just above that
* limit, forcing the idmap to use 4 levels of page tables while the
* kernel itself only uses 3). In this particular case, it doesn't
* matter which side of VA_BITS we use, as we're guaranteed not to
* conflict with anything.
*
* When using VHE, there are no separate hyp mappings and all KVM
* functionality is already mapped as part of the main kernel
* mappings, and none of this applies in that case.
*/
#define HYP_PAGE_OFFSET_HIGH_MASK ((UL(1) << VA_BITS) - 1)
#define HYP_PAGE_OFFSET_LOW_MASK ((UL(1) << (VA_BITS - 1)) - 1)
#ifdef __ASSEMBLY__
#include <asm/alternative.h>
#include <asm/cpufeature.h>
/*
* Convert a kernel VA into a HYP VA.
* reg: VA to be converted.
*
* This generates the following sequences:
* - High mask:
* and x0, x0, #HYP_PAGE_OFFSET_HIGH_MASK
* nop
* - Low mask:
* and x0, x0, #HYP_PAGE_OFFSET_HIGH_MASK
* and x0, x0, #HYP_PAGE_OFFSET_LOW_MASK
* - VHE:
* nop
* nop
*
* The "low mask" version works because the mask is a strict subset of
* the "high mask", hence performing the first mask for nothing.
* Should be completely invisible on any viable CPU.
*/
.macro kern_hyp_va reg
alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
and \reg, \reg, #HYP_PAGE_OFFSET_HIGH_MASK
alternative_else_nop_endif
alternative_if ARM64_HYP_OFFSET_LOW
and \reg, \reg, #HYP_PAGE_OFFSET_LOW_MASK
alternative_else_nop_endif
.endm
#else
#include <asm/pgalloc.h>
#include <asm/cache.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
static inline unsigned long __kern_hyp_va(unsigned long v)
{
asm volatile(ALTERNATIVE("and %0, %0, %1",
"nop",
ARM64_HAS_VIRT_HOST_EXTN)
: "+r" (v)
: "i" (HYP_PAGE_OFFSET_HIGH_MASK));
asm volatile(ALTERNATIVE("nop",
"and %0, %0, %1",
ARM64_HYP_OFFSET_LOW)
: "+r" (v)
: "i" (HYP_PAGE_OFFSET_LOW_MASK));
return v;
}
#define kern_hyp_va(v) ((typeof(v))(__kern_hyp_va((unsigned long)(v))))
/*
* We currently only support a 40bit IPA.
*/
#define KVM_PHYS_SHIFT (40)
#define KVM_PHYS_SIZE (1UL << KVM_PHYS_SHIFT)
#define KVM_PHYS_MASK (KVM_PHYS_SIZE - 1UL)
#include <asm/stage2_pgtable.h>
int create_hyp_mappings(void *from, void *to, pgprot_t prot);
int create_hyp_io_mappings(void *from, void *to, phys_addr_t);
void free_hyp_pgds(void);
void stage2_unmap_vm(struct kvm *kvm);
int kvm_alloc_stage2_pgd(struct kvm *kvm);
void kvm_free_stage2_pgd(struct kvm *kvm);
int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
phys_addr_t pa, unsigned long size, bool writable);
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_get_idmap_vector(void);
int kvm_mmu_init(void);
void kvm_clear_hyp_idmap(void);
#define kvm_set_pte(ptep, pte) set_pte(ptep, pte)
#define kvm_set_pmd(pmdp, pmd) set_pmd(pmdp, pmd)
static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
{
pte_val(pte) |= PTE_S2_RDWR;
return pte;
}
static inline pmd_t kvm_s2pmd_mkwrite(pmd_t pmd)
{
pmd_val(pmd) |= PMD_S2_RDWR;
return pmd;
}
static inline void kvm_set_s2pte_readonly(pte_t *pte)
{
pteval_t pteval;
unsigned long tmp;
asm volatile("// kvm_set_s2pte_readonly\n"
" prfm pstl1strm, %2\n"
"1: ldxr %0, %2\n"
" and %0, %0, %3 // clear PTE_S2_RDWR\n"
" orr %0, %0, %4 // set PTE_S2_RDONLY\n"
" stxr %w1, %0, %2\n"
" cbnz %w1, 1b\n"
: "=&r" (pteval), "=&r" (tmp), "+Q" (pte_val(*pte))
: "L" (~PTE_S2_RDWR), "L" (PTE_S2_RDONLY));
}
static inline bool kvm_s2pte_readonly(pte_t *pte)
{
return (pte_val(*pte) & PTE_S2_RDWR) == PTE_S2_RDONLY;
}
static inline void kvm_set_s2pmd_readonly(pmd_t *pmd)
{
kvm_set_s2pte_readonly((pte_t *)pmd);
}
static inline bool kvm_s2pmd_readonly(pmd_t *pmd)
{
return kvm_s2pte_readonly((pte_t *)pmd);
}
static inline bool kvm_page_empty(void *ptr)
{
struct page *ptr_page = virt_to_page(ptr);
return page_count(ptr_page) == 1;
}
#define hyp_pte_table_empty(ptep) kvm_page_empty(ptep)
#ifdef __PAGETABLE_PMD_FOLDED
#define hyp_pmd_table_empty(pmdp) (0)
#else
#define hyp_pmd_table_empty(pmdp) kvm_page_empty(pmdp)
#endif
#ifdef __PAGETABLE_PUD_FOLDED
#define hyp_pud_table_empty(pudp) (0)
#else
#define hyp_pud_table_empty(pudp) kvm_page_empty(pudp)
#endif
struct kvm;
#define kvm_flush_dcache_to_poc(a,l) __flush_dcache_area((a), (l))
static inline bool vcpu_has_cache_enabled(struct kvm_vcpu *vcpu)
{
return (vcpu_sys_reg(vcpu, SCTLR_EL1) & 0b101) == 0b101;
}
static inline void __coherent_cache_guest_page(struct kvm_vcpu *vcpu,
kvm_pfn_t pfn,
unsigned long size)
{
void *va = page_address(pfn_to_page(pfn));
kvm_flush_dcache_to_poc(va, size);
if (icache_is_aliasing()) {
/* any kind of VIPT cache */
__flush_icache_all();
} else if (is_kernel_in_hyp_mode() || !icache_is_vpipt()) {
/* PIPT or VPIPT at EL2 (see comment in __kvm_tlb_flush_vmid_ipa) */
flush_icache_range((unsigned long)va,
(unsigned long)va + size);
}
}
static inline void __kvm_flush_dcache_pte(pte_t pte)
{
struct page *page = pte_page(pte);
kvm_flush_dcache_to_poc(page_address(page), PAGE_SIZE);
}
static inline void __kvm_flush_dcache_pmd(pmd_t pmd)
{
struct page *page = pmd_page(pmd);
kvm_flush_dcache_to_poc(page_address(page), PMD_SIZE);
}
static inline void __kvm_flush_dcache_pud(pud_t pud)
{
struct page *page = pud_page(pud);
kvm_flush_dcache_to_poc(page_address(page), PUD_SIZE);
}
#define kvm_virt_to_phys(x) __pa_symbol(x)
void kvm_set_way_flush(struct kvm_vcpu *vcpu);
void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled);
static inline bool __kvm_cpu_uses_extended_idmap(void)
{
return __cpu_uses_extended_idmap();
}
static inline void __kvm_extend_hypmap(pgd_t *boot_hyp_pgd,
pgd_t *hyp_pgd,
pgd_t *merged_hyp_pgd,
unsigned long hyp_idmap_start)
{
int idmap_idx;
/*
* Use the first entry to access the HYP mappings. It is
* guaranteed to be free, otherwise we wouldn't use an
* extended idmap.
*/
VM_BUG_ON(pgd_val(merged_hyp_pgd[0]));
merged_hyp_pgd[0] = __pgd(__pa(hyp_pgd) | PMD_TYPE_TABLE);
/*
* Create another extended level entry that points to the boot HYP map,
* which contains an ID mapping of the HYP init code. We essentially
* merge the boot and runtime HYP maps by doing so, but they don't
* overlap anyway, so this is fine.
*/
idmap_idx = hyp_idmap_start >> VA_BITS;
VM_BUG_ON(pgd_val(merged_hyp_pgd[idmap_idx]));
merged_hyp_pgd[idmap_idx] = __pgd(__pa(boot_hyp_pgd) | PMD_TYPE_TABLE);
}
static inline unsigned int kvm_get_vmid_bits(void)
{
int reg = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
return (cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR1_VMIDBITS_SHIFT) == 2) ? 16 : 8;
}
#endif /* __ASSEMBLY__ */
#endif /* __ARM64_KVM_MMU_H__ */
