blob: c1a90dd022b8c151bf30152e7ddbfccf12676d19 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2020 Google LLC
* Author: Quentin Perret <qperret@google.com>
*/
#include <linux/kvm_host.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_pgtable.h>
#include <asm/stage2_pgtable.h>
#include <hyp/fault.h>
#include <nvhe/gfp.h>
#include <nvhe/memory.h>
#include <nvhe/mem_protect.h>
#include <nvhe/mm.h>
#define KVM_HOST_S2_FLAGS (KVM_PGTABLE_S2_NOFWB | KVM_PGTABLE_S2_IDMAP)
extern unsigned long hyp_nr_cpus;
struct host_kvm host_kvm;
static struct hyp_pool host_s2_pool;
const u8 pkvm_hyp_id = 1;
static void *host_s2_zalloc_pages_exact(size_t size)
{
void *addr = hyp_alloc_pages(&host_s2_pool, get_order(size));
hyp_split_page(hyp_virt_to_page(addr));
/*
* The size of concatenated PGDs is always a power of two of PAGE_SIZE,
* so there should be no need to free any of the tail pages to make the
* allocation exact.
*/
WARN_ON(size != (PAGE_SIZE << get_order(size)));
return addr;
}
static void *host_s2_zalloc_page(void *pool)
{
return hyp_alloc_pages(pool, 0);
}
static void host_s2_get_page(void *addr)
{
hyp_get_page(&host_s2_pool, addr);
}
static void host_s2_put_page(void *addr)
{
hyp_put_page(&host_s2_pool, addr);
}
static int prepare_s2_pool(void *pgt_pool_base)
{
unsigned long nr_pages, pfn;
int ret;
pfn = hyp_virt_to_pfn(pgt_pool_base);
nr_pages = host_s2_pgtable_pages();
ret = hyp_pool_init(&host_s2_pool, pfn, nr_pages, 0);
if (ret)
return ret;
host_kvm.mm_ops = (struct kvm_pgtable_mm_ops) {
.zalloc_pages_exact = host_s2_zalloc_pages_exact,
.zalloc_page = host_s2_zalloc_page,
.phys_to_virt = hyp_phys_to_virt,
.virt_to_phys = hyp_virt_to_phys,
.page_count = hyp_page_count,
.get_page = host_s2_get_page,
.put_page = host_s2_put_page,
};
return 0;
}
static void prepare_host_vtcr(void)
{
u32 parange, phys_shift;
/* The host stage 2 is id-mapped, so use parange for T0SZ */
parange = kvm_get_parange(id_aa64mmfr0_el1_sys_val);
phys_shift = id_aa64mmfr0_parange_to_phys_shift(parange);
host_kvm.arch.vtcr = kvm_get_vtcr(id_aa64mmfr0_el1_sys_val,
id_aa64mmfr1_el1_sys_val, phys_shift);
}
static bool host_stage2_force_pte_cb(u64 addr, u64 end, enum kvm_pgtable_prot prot);
int kvm_host_prepare_stage2(void *pgt_pool_base)
{
struct kvm_s2_mmu *mmu = &host_kvm.arch.mmu;
int ret;
prepare_host_vtcr();
hyp_spin_lock_init(&host_kvm.lock);
ret = prepare_s2_pool(pgt_pool_base);
if (ret)
return ret;
ret = __kvm_pgtable_stage2_init(&host_kvm.pgt, &host_kvm.arch,
&host_kvm.mm_ops, KVM_HOST_S2_FLAGS,
host_stage2_force_pte_cb);
if (ret)
return ret;
mmu->pgd_phys = __hyp_pa(host_kvm.pgt.pgd);
mmu->arch = &host_kvm.arch;
mmu->pgt = &host_kvm.pgt;
WRITE_ONCE(mmu->vmid.vmid_gen, 0);
WRITE_ONCE(mmu->vmid.vmid, 0);
return 0;
}
int __pkvm_prot_finalize(void)
{
struct kvm_s2_mmu *mmu = &host_kvm.arch.mmu;
struct kvm_nvhe_init_params *params = this_cpu_ptr(&kvm_init_params);
if (params->hcr_el2 & HCR_VM)
return -EPERM;
params->vttbr = kvm_get_vttbr(mmu);
params->vtcr = host_kvm.arch.vtcr;
params->hcr_el2 |= HCR_VM;
kvm_flush_dcache_to_poc(params, sizeof(*params));
write_sysreg(params->hcr_el2, hcr_el2);
__load_stage2(&host_kvm.arch.mmu, &host_kvm.arch);
/*
* Make sure to have an ISB before the TLB maintenance below but only
* when __load_stage2() doesn't include one already.
*/
asm(ALTERNATIVE("isb", "nop", ARM64_WORKAROUND_SPECULATIVE_AT));
/* Invalidate stale HCR bits that may be cached in TLBs */
__tlbi(vmalls12e1);
dsb(nsh);
isb();
return 0;
}
static int host_stage2_unmap_dev_all(void)
{
struct kvm_pgtable *pgt = &host_kvm.pgt;
struct memblock_region *reg;
u64 addr = 0;
int i, ret;
/* Unmap all non-memory regions to recycle the pages */
for (i = 0; i < hyp_memblock_nr; i++, addr = reg->base + reg->size) {
reg = &hyp_memory[i];
ret = kvm_pgtable_stage2_unmap(pgt, addr, reg->base - addr);
if (ret)
return ret;
}
return kvm_pgtable_stage2_unmap(pgt, addr, BIT(pgt->ia_bits) - addr);
}
struct kvm_mem_range {
u64 start;
u64 end;
};
static bool find_mem_range(phys_addr_t addr, struct kvm_mem_range *range)
{
int cur, left = 0, right = hyp_memblock_nr;
struct memblock_region *reg;
phys_addr_t end;
range->start = 0;
range->end = ULONG_MAX;
/* The list of memblock regions is sorted, binary search it */
while (left < right) {
cur = (left + right) >> 1;
reg = &hyp_memory[cur];
end = reg->base + reg->size;
if (addr < reg->base) {
right = cur;
range->end = reg->base;
} else if (addr >= end) {
left = cur + 1;
range->start = end;
} else {
range->start = reg->base;
range->end = end;
return true;
}
}
return false;
}
bool addr_is_memory(phys_addr_t phys)
{
struct kvm_mem_range range;
return find_mem_range(phys, &range);
}
static bool is_in_mem_range(u64 addr, struct kvm_mem_range *range)
{
return range->start <= addr && addr < range->end;
}
static bool range_is_memory(u64 start, u64 end)
{
struct kvm_mem_range r;
if (!find_mem_range(start, &r))
return false;
return is_in_mem_range(end - 1, &r);
}
static inline int __host_stage2_idmap(u64 start, u64 end,
enum kvm_pgtable_prot prot)
{
return kvm_pgtable_stage2_map(&host_kvm.pgt, start, end - start, start,
prot, &host_s2_pool);
}
/*
* The pool has been provided with enough pages to cover all of memory with
* page granularity, but it is difficult to know how much of the MMIO range
* we will need to cover upfront, so we may need to 'recycle' the pages if we
* run out.
*/
#define host_stage2_try(fn, ...) \
({ \
int __ret; \
hyp_assert_lock_held(&host_kvm.lock); \
__ret = fn(__VA_ARGS__); \
if (__ret == -ENOMEM) { \
__ret = host_stage2_unmap_dev_all(); \
if (!__ret) \
__ret = fn(__VA_ARGS__); \
} \
__ret; \
})
static inline bool range_included(struct kvm_mem_range *child,
struct kvm_mem_range *parent)
{
return parent->start <= child->start && child->end <= parent->end;
}
static int host_stage2_adjust_range(u64 addr, struct kvm_mem_range *range)
{
struct kvm_mem_range cur;
kvm_pte_t pte;
u32 level;
int ret;
hyp_assert_lock_held(&host_kvm.lock);
ret = kvm_pgtable_get_leaf(&host_kvm.pgt, addr, &pte, &level);
if (ret)
return ret;
if (kvm_pte_valid(pte))
return -EAGAIN;
if (pte)
return -EPERM;
do {
u64 granule = kvm_granule_size(level);
cur.start = ALIGN_DOWN(addr, granule);
cur.end = cur.start + granule;
level++;
} while ((level < KVM_PGTABLE_MAX_LEVELS) &&
!(kvm_level_supports_block_mapping(level) &&
range_included(&cur, range)));
*range = cur;
return 0;
}
int host_stage2_idmap_locked(phys_addr_t addr, u64 size,
enum kvm_pgtable_prot prot)
{
hyp_assert_lock_held(&host_kvm.lock);
return host_stage2_try(__host_stage2_idmap, addr, addr + size, prot);
}
int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id)
{
hyp_assert_lock_held(&host_kvm.lock);
return host_stage2_try(kvm_pgtable_stage2_set_owner, &host_kvm.pgt,
addr, size, &host_s2_pool, owner_id);
}
static bool host_stage2_force_pte_cb(u64 addr, u64 end, enum kvm_pgtable_prot prot)
{
/*
* Block mappings must be used with care in the host stage-2 as a
* kvm_pgtable_stage2_map() operation targeting a page in the range of
* an existing block will delete the block under the assumption that
* mappings in the rest of the block range can always be rebuilt lazily.
* That assumption is correct for the host stage-2 with RWX mappings
* targeting memory or RW mappings targeting MMIO ranges (see
* host_stage2_idmap() below which implements some of the host memory
* abort logic). However, this is not safe for any other mappings where
* the host stage-2 page-table is in fact the only place where this
* state is stored. In all those cases, it is safer to use page-level
* mappings, hence avoiding to lose the state because of side-effects in
* kvm_pgtable_stage2_map().
*/
if (range_is_memory(addr, end))
return prot != PKVM_HOST_MEM_PROT;
else
return prot != PKVM_HOST_MMIO_PROT;
}
static int host_stage2_idmap(u64 addr)
{
struct kvm_mem_range range;
bool is_memory = find_mem_range(addr, &range);
enum kvm_pgtable_prot prot;
int ret;
prot = is_memory ? PKVM_HOST_MEM_PROT : PKVM_HOST_MMIO_PROT;
hyp_spin_lock(&host_kvm.lock);
ret = host_stage2_adjust_range(addr, &range);
if (ret)
goto unlock;
ret = host_stage2_idmap_locked(range.start, range.end - range.start, prot);
unlock:
hyp_spin_unlock(&host_kvm.lock);
return ret;
}
static inline bool check_prot(enum kvm_pgtable_prot prot,
enum kvm_pgtable_prot required,
enum kvm_pgtable_prot denied)
{
return (prot & (required | denied)) == required;
}
int __pkvm_host_share_hyp(u64 pfn)
{
phys_addr_t addr = hyp_pfn_to_phys(pfn);
enum kvm_pgtable_prot prot, cur;
void *virt = __hyp_va(addr);
enum pkvm_page_state state;
kvm_pte_t pte;
int ret;
if (!addr_is_memory(addr))
return -EINVAL;
hyp_spin_lock(&host_kvm.lock);
hyp_spin_lock(&pkvm_pgd_lock);
ret = kvm_pgtable_get_leaf(&host_kvm.pgt, addr, &pte, NULL);
if (ret)
goto unlock;
if (!pte)
goto map_shared;
/*
* Check attributes in the host stage-2 PTE. We need the page to be:
* - mapped RWX as we're sharing memory;
* - not borrowed, as that implies absence of ownership.
* Otherwise, we can't let it got through
*/
cur = kvm_pgtable_stage2_pte_prot(pte);
prot = pkvm_mkstate(0, PKVM_PAGE_SHARED_BORROWED);
if (!check_prot(cur, PKVM_HOST_MEM_PROT, prot)) {
ret = -EPERM;
goto unlock;
}
state = pkvm_getstate(cur);
if (state == PKVM_PAGE_OWNED)
goto map_shared;
/*
* Tolerate double-sharing the same page, but this requires
* cross-checking the hypervisor stage-1.
*/
if (state != PKVM_PAGE_SHARED_OWNED) {
ret = -EPERM;
goto unlock;
}
ret = kvm_pgtable_get_leaf(&pkvm_pgtable, (u64)virt, &pte, NULL);
if (ret)
goto unlock;
/*
* If the page has been shared with the hypervisor, it must be
* already mapped as SHARED_BORROWED in its stage-1.
*/
cur = kvm_pgtable_hyp_pte_prot(pte);
prot = pkvm_mkstate(PAGE_HYP, PKVM_PAGE_SHARED_BORROWED);
if (!check_prot(cur, prot, ~prot))
ret = -EPERM;
goto unlock;
map_shared:
/*
* If the page is not yet shared, adjust mappings in both page-tables
* while both locks are held.
*/
prot = pkvm_mkstate(PAGE_HYP, PKVM_PAGE_SHARED_BORROWED);
ret = pkvm_create_mappings_locked(virt, virt + PAGE_SIZE, prot);
BUG_ON(ret);
prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_OWNED);
ret = host_stage2_idmap_locked(addr, PAGE_SIZE, prot);
BUG_ON(ret);
unlock:
hyp_spin_unlock(&pkvm_pgd_lock);
hyp_spin_unlock(&host_kvm.lock);
return ret;
}
void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
{
struct kvm_vcpu_fault_info fault;
u64 esr, addr;
int ret = 0;
esr = read_sysreg_el2(SYS_ESR);
BUG_ON(!__get_fault_info(esr, &fault));
addr = (fault.hpfar_el2 & HPFAR_MASK) << 8;
ret = host_stage2_idmap(addr);
BUG_ON(ret && ret != -EAGAIN);
}