From 26117e4c636c813be4fa31e9ec9410b7d02ced5c Mon Sep 17 00:00:00 2001 From: Quentin Perret Date: Wed, 18 Dec 2024 19:40:54 +0000 Subject: [PATCH] KVM: arm64: Introduce __pkvm_host_wrprotect_guest() Introduce a new hypercall to remove the write permission from a non-protected guest stage-2 mapping. This will be used for e.g. enabling dirty logging. Tested-by: Fuad Tabba Reviewed-by: Fuad Tabba Signed-off-by: Quentin Perret Link: https://lore.kernel.org/r/20241218194059.3670226-14-qperret@google.com Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_asm.h | 1 + arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 1 + arch/arm64/kvm/hyp/nvhe/hyp-main.c | 21 +++++++++++++++++++ arch/arm64/kvm/hyp/nvhe/mem_protect.c | 19 +++++++++++++++++ 4 files changed, 42 insertions(+) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 66ee8542dcc9..8663a588cf34 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -68,6 +68,7 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___pkvm_host_share_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, __KVM_HOST_SMCCC_FUNC___kvm_adjust_pc, __KVM_HOST_SMCCC_FUNC___kvm_vcpu_run, __KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context, diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h index 181aec2d5bc1..0bbfb0e1734c 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -43,6 +43,7 @@ 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); int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot); +int __pkvm_host_wrprotect_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm); bool addr_is_memory(phys_addr_t phys); int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot); diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 287e4ee93ef2..98d317735107 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -283,6 +283,26 @@ static void handle___pkvm_host_relax_perms_guest(struct kvm_cpu_context *host_ct cpu_reg(host_ctxt, 1) = ret; } +static void handle___pkvm_host_wrprotect_guest(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1); + DECLARE_REG(u64, gfn, host_ctxt, 2); + struct pkvm_hyp_vm *hyp_vm; + int ret = -EINVAL; + + if (!is_protected_kvm_enabled()) + goto out; + + hyp_vm = get_np_pkvm_hyp_vm(handle); + if (!hyp_vm) + goto out; + + ret = __pkvm_host_wrprotect_guest(gfn, hyp_vm); + put_pkvm_hyp_vm(hyp_vm); +out: + cpu_reg(host_ctxt, 1) = ret; +} + static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt) { DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1); @@ -495,6 +515,7 @@ static const hcall_t host_hcall[] = { HANDLE_FUNC(__pkvm_host_share_guest), HANDLE_FUNC(__pkvm_host_unshare_guest), HANDLE_FUNC(__pkvm_host_relax_perms_guest), + HANDLE_FUNC(__pkvm_host_wrprotect_guest), HANDLE_FUNC(__kvm_adjust_pc), HANDLE_FUNC(__kvm_vcpu_run), HANDLE_FUNC(__kvm_flush_vm_context), diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index aa8e0408aebb..94e4251b5077 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -1511,3 +1511,22 @@ int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_ return ret; } + +int __pkvm_host_wrprotect_guest(u64 gfn, struct pkvm_hyp_vm *vm) +{ + u64 ipa = hyp_pfn_to_phys(gfn); + u64 phys; + int ret; + + host_lock_component(); + guest_lock_component(vm); + + ret = __check_host_shared_guest(vm, &phys, ipa); + if (!ret) + ret = kvm_pgtable_stage2_wrprotect(&vm->pgt, ipa, PAGE_SIZE); + + guest_unlock_component(vm); + host_unlock_component(); + + return ret; +}