diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index efbad6f97f89..0e4a0b179a85 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -63,6 +63,7 @@ enum __kvm_host_smccc_func { /* Hypercalls available after pKVM finalisation */ __KVM_HOST_SMCCC_FUNC___pkvm_host_share_hyp, __KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_hyp, + __KVM_HOST_SMCCC_FUNC___pkvm_host_reclaim_page, __KVM_HOST_SMCCC_FUNC___pkvm_host_donate_guest, __KVM_HOST_SMCCC_FUNC___kvm_adjust_pc, __KVM_HOST_SMCCC_FUNC___kvm_vcpu_run, diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 542f05684f4a..97b40bd1d429 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -195,6 +195,10 @@ static void kvm_shadow_destroy(struct kvm *kvm) ppages = &kvm->arch.pkvm.pinned_pages; list_for_each_entry_safe(ppage, tmp, ppages, link) { + WARN_ON(kvm_call_hyp_nvhe(__pkvm_host_reclaim_page, + page_to_pfn(ppage->page))); + cond_resched(); + account_locked_vm(mm, 1, false); unpin_user_pages_dirty_lock(&ppage->page, 1, true); list_del(&ppage->link); diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h index 998a54a52093..72a7c4a58fa6 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -54,12 +54,14 @@ extern struct host_kvm host_kvm; typedef u32 pkvm_id; static const pkvm_id pkvm_host_id = 0; static const pkvm_id pkvm_hyp_id = (1 << 16); +static const pkvm_id pkvm_host_poison = pkvm_hyp_id + 1; extern unsigned long hyp_nr_cpus; int __pkvm_prot_finalize(void); int __pkvm_host_share_hyp(u64 pfn); int __pkvm_host_unshare_hyp(u64 pfn); +int __pkvm_host_reclaim_page(u64 pfn); int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages); int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages); int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct kvm_vcpu *vcpu); diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 32997ba4abf0..7d61b5fad4a4 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -811,6 +811,13 @@ static void handle___pkvm_host_unshare_hyp(struct kvm_cpu_context *host_ctxt) cpu_reg(host_ctxt, 1) = __pkvm_host_unshare_hyp(pfn); } +static void handle___pkvm_host_reclaim_page(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(u64, pfn, host_ctxt, 1); + + cpu_reg(host_ctxt, 1) = __pkvm_host_reclaim_page(pfn); +} + static void handle___pkvm_create_private_mapping(struct kvm_cpu_context *host_ctxt) { DECLARE_REG(phys_addr_t, phys, host_ctxt, 1); @@ -860,6 +867,7 @@ static const hcall_t host_hcall[] = { HANDLE_FUNC(__pkvm_host_share_hyp), HANDLE_FUNC(__pkvm_host_unshare_hyp), + HANDLE_FUNC(__pkvm_host_reclaim_page), HANDLE_FUNC(__pkvm_host_donate_guest), HANDLE_FUNC(__kvm_adjust_pc), HANDLE_FUNC(__kvm_vcpu_run), diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 4a6b4d1a0795..4baf271b7c51 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -304,12 +304,7 @@ static int reclaim_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, * stage-2 so no need to waste effort trying to keep it in sync. */ phys = kvm_pte_to_phys(pte); - BUG_ON(host_stage2_set_owner_locked(phys, PAGE_SIZE, pkvm_host_id)); - - /* - * XXX: if protected guest mark the page 'dirty' instead, and zero it - * lazily on host s2 aborts. - */ + BUG_ON(host_stage2_set_owner_locked(phys, PAGE_SIZE, pkvm_host_poison)); return 0; } @@ -523,6 +518,11 @@ static kvm_pte_t kvm_init_invalid_leaf_owner(pkvm_id owner_id) return FIELD_PREP(KVM_INVALID_PTE_OWNER_MASK, owner_id); } +static pkvm_id kvm_get_owner_id(kvm_pte_t pte) +{ + return FIELD_GET(KVM_INVALID_PTE_OWNER_MASK, pte); +} + int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, pkvm_id owner_id) { @@ -1767,3 +1767,55 @@ int __pkvm_host_donate_guest(u64 pfn, u64 gfn, struct kvm_vcpu *vcpu) return ret; } + +static int hyp_zero_page(phys_addr_t phys) +{ + void *addr; + + addr = hyp_fixmap_map(phys); + if (!addr) + return -EINVAL; + memset(addr, 0, PAGE_SIZE); + __clean_dcache_guest_page(addr, PAGE_SIZE); + + return hyp_fixmap_unmap(); +} + +int __pkvm_host_reclaim_page(u64 pfn) +{ + u64 addr = hyp_pfn_to_phys(pfn); + enum pkvm_page_state state; + kvm_pte_t pte; + int ret; + + host_lock_component(); + + ret = kvm_pgtable_get_leaf(&host_kvm.pgt, addr, &pte, NULL); + if (ret) + goto unlock; + + if (kvm_pte_valid(pte)) { + state = host_get_page_state(pte); + ret = (state == PKVM_PAGE_OWNED) ? 0 : -EPERM; + goto unlock; + } + + switch (kvm_get_owner_id(pte)) { + case pkvm_host_id: + ret = 0; + break; + case pkvm_host_poison: + ret = hyp_zero_page(addr); + if (ret) + goto unlock; + ret = host_stage2_set_owner_locked(addr, PAGE_SIZE, pkvm_host_id); + break; + default: + ret = -EPERM; + } + +unlock: + host_unlock_component(); + + return ret; +}