KVM: arm64: Introduce hypercall for host-to-guest donations In preparation for supporting protected guests, introduce a new memory transition hypercall allowing the donation of pages to pVMs. Signed-off-by: Quentin Perret <qperret@google.com>
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 6d3d11f..45d7141 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h
@@ -64,7 +64,7 @@ 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_share_guest, + __KVM_HOST_SMCCC_FUNC___pkvm_host_map_guest, __KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_guest, __KVM_HOST_SMCCC_FUNC___pkvm_host_relax_perms_guest, __KVM_HOST_SMCCC_FUNC___pkvm_host_wrprotect_guest,
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h index 6b9d274..adf7f4b 100644 --- a/arch/arm64/include/asm/kvm_pgtable.h +++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -93,7 +93,7 @@ typedef u64 kvm_pte_t; KVM_PTE_LEAF_ATTR_HI_S2_XN) #define KVM_INVALID_PTE_OWNER_MASK GENMASK(9, 2) -#define KVM_MAX_OWNER_ID 1 +#define KVM_MAX_OWNER_ID 3 /* * Used to indicate a pte for which a 'break-before-make' sequence is in
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h index ea0a704..15fabb7 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -28,6 +28,7 @@ enum pkvm_component_id { PKVM_ID_HOST, PKVM_ID_HYP, PKVM_ID_FFA, + PKVM_ID_GUEST, }; extern unsigned long hyp_nr_cpus; @@ -39,6 +40,7 @@ int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages); int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages); int __pkvm_host_share_ffa(u64 pfn, u64 nr_pages); int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages); +int __pkvm_host_donate_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu); int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot); int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index d60303c..688da95 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -777,7 +777,7 @@ static int pkvm_refill_memcache(struct pkvm_hyp_vcpu *hyp_vcpu) &host_vcpu->arch.pkvm_memcache); } -static void handle___pkvm_host_share_guest(struct kvm_cpu_context *host_ctxt) +static void handle___pkvm_host_map_guest(struct kvm_cpu_context *host_ctxt) { DECLARE_REG(u64, pfn, host_ctxt, 1); DECLARE_REG(u64, gfn, host_ctxt, 2); @@ -789,14 +789,17 @@ static void handle___pkvm_host_share_guest(struct kvm_cpu_context *host_ctxt) goto out; hyp_vcpu = pkvm_get_loaded_hyp_vcpu(); - if (!hyp_vcpu || pkvm_hyp_vcpu_is_protected(hyp_vcpu)) + if (!hyp_vcpu) goto out; ret = pkvm_refill_memcache(hyp_vcpu); if (ret) goto out; - ret = __pkvm_host_share_guest(pfn, gfn, hyp_vcpu, prot); + if (pkvm_hyp_vcpu_is_protected(hyp_vcpu)) + ret = __pkvm_host_donate_guest(pfn, gfn, hyp_vcpu); + else + ret = __pkvm_host_share_guest(pfn, gfn, hyp_vcpu, prot); out: cpu_reg(host_ctxt, 1) = ret; } @@ -1131,7 +1134,7 @@ static const hcall_t host_hcall[] = { HANDLE_FUNC(__pkvm_host_share_hyp), HANDLE_FUNC(__pkvm_host_unshare_hyp), - HANDLE_FUNC(__pkvm_host_share_guest), + HANDLE_FUNC(__pkvm_host_map_guest), HANDLE_FUNC(__pkvm_host_unshare_guest), HANDLE_FUNC(__pkvm_host_relax_perms_guest), HANDLE_FUNC(__pkvm_host_wrprotect_guest),
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 1055f05d4..72a540d 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -935,6 +935,36 @@ int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages) return ret; } +int __pkvm_host_donate_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu) +{ + struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu); + u64 phys = hyp_pfn_to_phys(pfn); + u64 ipa = hyp_pfn_to_phys(gfn); + int ret; + + host_lock_component(); + guest_lock_component(vm); + + ret = __host_check_page_state_range(phys, PAGE_SIZE, PKVM_PAGE_OWNED); + if (ret) + goto unlock; + + ret = __guest_check_page_state_range(vcpu, ipa, PAGE_SIZE, PKVM_NOPAGE); + if (ret) + goto unlock; + + WARN_ON(host_stage2_set_owner_locked(phys, PAGE_SIZE, PKVM_ID_GUEST)); + WARN_ON(kvm_pgtable_stage2_map(&vm->pgt, ipa, PAGE_SIZE, phys, + pkvm_mkstate(KVM_PGTABLE_PROT_RWX, PKVM_PAGE_OWNED), + &vcpu->vcpu.arch.pkvm_memcache, 0)); + +unlock: + guest_unlock_component(vm); + host_unlock_component(); + + return ret; +} + int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot) {
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c index 0f89157..0906b63 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c
@@ -364,7 +364,7 @@ int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size, return -EINVAL; lockdep_assert_held_write(&kvm->mmu_lock); - ret = kvm_call_hyp_nvhe(__pkvm_host_share_guest, pfn, gfn, prot); + ret = kvm_call_hyp_nvhe(__pkvm_host_map_guest, pfn, gfn, prot); if (ret) { /* Is the gfn already mapped due to a racing vCPU? */ if (ret == -EPERM)