u64 id_aa64mmfr0_el1_sys_val;
u64 id_aa64mmfr1_el1_sys_val;
-static const u8 pkvm_hyp_id = 1;
+const u8 pkvm_hyp_id = 1;
static void *host_s2_zalloc_pages_exact(size_t size)
{
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;
if (ret)
return ret;
- ret = kvm_pgtable_stage2_init_flags(&host_kvm.pgt, &host_kvm.arch,
- &host_kvm.mm_ops, KVM_HOST_S2_FLAGS);
+ 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;
- mmu->vmid.vmid_gen = 0;
- mmu->vmid.vmid = 0;
+ WRITE_ONCE(mmu->vmid.vmid_gen, 0);
+ WRITE_ONCE(mmu->vmid.vmid, 0);
return 0;
}
kvm_flush_dcache_to_poc(params, sizeof(*params));
write_sysreg(params->hcr_el2, hcr_el2);
- __load_stage2(&host_kvm.arch.mmu, host_kvm.arch.vtcr);
+ __load_stage2(&host_kvm.arch.mmu, &host_kvm.arch);
/*
* Make sure to have an ISB before the TLB maintenance below but only
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;
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 r1, r2;
+ struct kvm_mem_range r;
- if (!find_mem_range(start, &r1) || !find_mem_range(end - 1, &r2))
- return false;
- if (r1.start != r2.start)
+ if (!find_mem_range(start, &r))
return false;
- return true;
+ return is_in_mem_range(end - 1, &r);
}
static inline int __host_stage2_idmap(u64 start, u64 end,
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)
{
- enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R | KVM_PGTABLE_PROT_W;
struct kvm_mem_range range;
bool is_memory = find_mem_range(addr, &range);
+ enum kvm_pgtable_prot prot;
int ret;
- if (is_memory)
- prot |= KVM_PGTABLE_PROT_X;
+ prot = is_memory ? PKVM_HOST_MEM_PROT : PKVM_HOST_MMIO_PROT;
hyp_spin_lock(&host_kvm.lock);
- ret = kvm_pgtable_stage2_find_range(&host_kvm.pgt, addr, prot, &range);
+ ret = host_stage2_adjust_range(addr, &range);
if (ret)
goto unlock;
- ret = __host_stage2_idmap(range.start, range.end, prot);
- if (ret != -ENOMEM)
+ 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;
/*
- * 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.
+ * 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
*/
- ret = host_stage2_unmap_dev_all();
- if (ret)
+ 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;
+ }
- ret = __host_stage2_idmap(range.start, range.end, prot);
+ state = pkvm_getstate(cur);
+ if (state == PKVM_PAGE_OWNED)
+ goto map_shared;
-unlock:
- hyp_spin_unlock(&host_kvm.lock);
+ /*
+ * 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;
+ }
- return ret;
-}
+ ret = kvm_pgtable_get_leaf(&pkvm_pgtable, (u64)virt, &pte, NULL);
+ if (ret)
+ goto unlock;
-int __pkvm_mark_hyp(phys_addr_t start, phys_addr_t end)
-{
- int ret;
+ /*
+ * 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:
/*
- * host_stage2_unmap_dev_all() currently relies on MMIO mappings being
- * non-persistent, so don't allow changing page ownership in MMIO range.
+ * If the page is not yet shared, adjust mappings in both page-tables
+ * while both locks are held.
*/
- if (!range_is_memory(start, end))
- return -EINVAL;
+ prot = pkvm_mkstate(PAGE_HYP, PKVM_PAGE_SHARED_BORROWED);
+ ret = pkvm_create_mappings_locked(virt, virt + PAGE_SIZE, prot);
+ BUG_ON(ret);
- hyp_spin_lock(&host_kvm.lock);
- ret = kvm_pgtable_stage2_set_owner(&host_kvm.pgt, start, end - start,
- &host_s2_pool, pkvm_hyp_id);
+ 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 != -EAGAIN ? ret : 0;
+ return ret;
}
void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
projects / linux-2.6-microblaze.git / blobdiff