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Tue, 17 Dec 2024 11:29:03 +0000 Date: Tue, 17 Dec 2024 11:29:03 +0000 Message-ID: <86wmfyr1j4.wl-maz@kernel.org> From: Marc Zyngier To: Quentin Perret Cc: Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Fuad Tabba , Vincent Donnefort , Sebastian Ene , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 11/18] KVM: arm64: Introduce __pkvm_host_unshare_guest() In-Reply-To: <20241216175803.2716565-12-qperret@google.com> References: <20241216175803.2716565-1-qperret@google.com> <20241216175803.2716565-12-qperret@google.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/29.4 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: qperret@google.com, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, tabba@google.com, vdonnefort@google.com, sebastianene@google.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Mon, 16 Dec 2024 17:57:56 +0000, Quentin Perret wrote: > > In preparation for letting the host unmap pages from non-protected > guests, introduce a new hypercall implementing the host-unshare-guest > transition. > > Signed-off-by: Quentin Perret > --- > arch/arm64/include/asm/kvm_asm.h | 1 + > arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 1 + > arch/arm64/kvm/hyp/include/nvhe/pkvm.h | 6 ++ > arch/arm64/kvm/hyp/nvhe/hyp-main.c | 21 ++++++ > arch/arm64/kvm/hyp/nvhe/mem_protect.c | 67 +++++++++++++++++++ > arch/arm64/kvm/hyp/nvhe/pkvm.c | 12 ++++ > 6 files changed, 108 insertions(+) > > diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h > index 449337f5b2a3..0b6c4d325134 100644 > --- a/arch/arm64/include/asm/kvm_asm.h > +++ b/arch/arm64/include/asm/kvm_asm.h > @@ -66,6 +66,7 @@ enum __kvm_host_smccc_func { > __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_unshare_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 a7976e50f556..e528a42ed60e 100644 > --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h > +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h > @@ -40,6 +40,7 @@ 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_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); > > 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/include/nvhe/pkvm.h b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h > index be52c5b15e21..0cc2a429f1fb 100644 > --- a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h > +++ b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h > @@ -64,6 +64,11 @@ static inline bool pkvm_hyp_vcpu_is_protected(struct pkvm_hyp_vcpu *hyp_vcpu) > return vcpu_is_protected(&hyp_vcpu->vcpu); > } > > +static inline bool pkvm_hyp_vm_is_protected(struct pkvm_hyp_vm *hyp_vm) > +{ > + return kvm_vm_is_protected(&hyp_vm->kvm); > +} > + > void pkvm_hyp_vm_table_init(void *tbl); > > int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva, > @@ -78,6 +83,7 @@ void pkvm_put_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu); > struct pkvm_hyp_vcpu *pkvm_get_loaded_hyp_vcpu(void); > > struct pkvm_hyp_vm *get_pkvm_hyp_vm(pkvm_handle_t handle); > +struct pkvm_hyp_vm *get_np_pkvm_hyp_vm(pkvm_handle_t handle); > void put_pkvm_hyp_vm(struct pkvm_hyp_vm *hyp_vm); > > #endif /* __ARM64_KVM_NVHE_PKVM_H__ */ > diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c > index d659462fbf5d..3c3a27c985a2 100644 > --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c > +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c > @@ -244,6 +244,26 @@ static void handle___pkvm_host_share_guest(struct kvm_cpu_context *host_ctxt) > cpu_reg(host_ctxt, 1) = ret; > } > > +static void handle___pkvm_host_unshare_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_unshare_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); > @@ -454,6 +474,7 @@ 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_unshare_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 fb9592e721cf..30243b7922f1 100644 > --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c > +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c > @@ -1421,3 +1421,70 @@ int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu, > > return ret; > } > + > +static int __check_host_shared_guest(struct pkvm_hyp_vm *vm, u64 *__phys, u64 ipa) > +{ > + enum pkvm_page_state state; > + struct hyp_page *page; > + kvm_pte_t pte; > + u64 phys; > + s8 level; > + int ret; > + > + ret = kvm_pgtable_get_leaf(&vm->pgt, ipa, &pte, &level); > + if (ret) > + return ret; > + if (level != KVM_PGTABLE_LAST_LEVEL) So there is still a very strong assumption that a guest is only provided page mappings, and no blocks? Thanks, M. -- Without deviation from the norm, progress is not possible.