| Message ID | 20241203103735.2267589-13-qperret@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: arm64: Non-protected guest stage-2 support for pKVM | expand |
Hi Quentin, On Tue, 3 Dec 2024 at 10:38, Quentin Perret <qperret@google.com> wrote: > > Introduce a new hypercall allowing the host to relax the stage-2 > permissions of mappings in a non-protected guest page-table. It will be > used later once we start allowing RO memslots and dirty logging. > > Signed-off-by: Quentin Perret <qperret@google.com> > --- > 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 | 20 ++++++++++++++++ > arch/arm64/kvm/hyp/nvhe/mem_protect.c | 23 +++++++++++++++++++ > 4 files changed, 45 insertions(+) > > diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h > index 0b6c4d325134..5d51933e44fb 100644 > --- a/arch/arm64/include/asm/kvm_asm.h > +++ b/arch/arm64/include/asm/kvm_asm.h > @@ -67,6 +67,7 @@ enum __kvm_host_smccc_func { > __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___pkvm_host_relax_guest_perms, > __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 e528a42ed60e..db0dd83c2457 100644 > --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h > +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h > @@ -41,6 +41,7 @@ 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); > +int __pkvm_host_relax_guest_perms(u64 gfn, enum kvm_pgtable_prot prot, struct pkvm_hyp_vcpu *vcpu); The parameters are the same as __pkvm_host_share_guest, but in a different order. I looked ahead at later patches in the series, and similar issues regarding parameter type and ordering, so I won't mention it for the later patches. > 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 04a9053ae1d5..60dd56bbd743 100644 > --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c > +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c > @@ -267,6 +267,25 @@ static void handle___pkvm_host_unshare_guest(struct kvm_cpu_context *host_ctxt) > cpu_reg(host_ctxt, 1) = ret; > } > > +static void handle___pkvm_host_relax_guest_perms(struct kvm_cpu_context *host_ctxt) > +{ > + DECLARE_REG(u64, gfn, host_ctxt, 1); > + DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 2); > + struct pkvm_hyp_vcpu *hyp_vcpu; > + int ret = -EINVAL; > + > + if (!is_protected_kvm_enabled()) > + goto out; > + > + hyp_vcpu = pkvm_get_loaded_hyp_vcpu(); > + if (!hyp_vcpu || pkvm_hyp_vcpu_is_protected(hyp_vcpu)) > + goto out; > + > + ret = __pkvm_host_relax_guest_perms(gfn, prot, hyp_vcpu); > +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); > @@ -478,6 +497,7 @@ static const hcall_t host_hcall[] = { > HANDLE_FUNC(__pkvm_host_unshare_hyp), > HANDLE_FUNC(__pkvm_host_share_guest), > HANDLE_FUNC(__pkvm_host_unshare_guest), > + HANDLE_FUNC(__pkvm_host_relax_guest_perms), > 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 aa27a3e42e5e..d4b28e93e790 100644 > --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c > +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c > @@ -1480,3 +1480,26 @@ int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm) > > return ret; > } > + > +int __pkvm_host_relax_guest_perms(u64 gfn, enum kvm_pgtable_prot prot, struct pkvm_hyp_vcpu *vcpu) > +{ > + struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu); > + u64 ipa = hyp_pfn_to_phys(gfn); > + u64 phys; > + int ret; > + > + if ((prot & KVM_PGTABLE_PROT_RWX) != prot) > + return -EPERM; Why not + if (prot & ~KVM_PGTABLE_PROT_RWX) Simpler and consistent with similar checks in the file (e.g., __pkvm_host_share_guest) Cheers, /fuad > + > + host_lock_component(); > + guest_lock_component(vm); > + > + ret = __check_host_unshare_guest(vm, &phys, ipa); > + if (!ret) > + ret = kvm_pgtable_stage2_relax_perms(&vm->pgt, ipa, prot, 0); > + > + guest_unlock_component(vm); > + host_unlock_component(); > + > + return ret; > +} > -- > 2.47.0.338.g60cca15819-goog >
On Tuesday 10 Dec 2024 at 14:56:05 (+0000), Fuad Tabba wrote: > Hi Quentin, > > On Tue, 3 Dec 2024 at 10:38, Quentin Perret <qperret@google.com> wrote: > > > > Introduce a new hypercall allowing the host to relax the stage-2 > > permissions of mappings in a non-protected guest page-table. It will be > > used later once we start allowing RO memslots and dirty logging. > > > > Signed-off-by: Quentin Perret <qperret@google.com> > > --- > > 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 | 20 ++++++++++++++++ > > arch/arm64/kvm/hyp/nvhe/mem_protect.c | 23 +++++++++++++++++++ > > 4 files changed, 45 insertions(+) > > > > diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h > > index 0b6c4d325134..5d51933e44fb 100644 > > --- a/arch/arm64/include/asm/kvm_asm.h > > +++ b/arch/arm64/include/asm/kvm_asm.h > > @@ -67,6 +67,7 @@ enum __kvm_host_smccc_func { > > __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___pkvm_host_relax_guest_perms, > > __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 e528a42ed60e..db0dd83c2457 100644 > > --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h > > +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h > > @@ -41,6 +41,7 @@ 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); > > +int __pkvm_host_relax_guest_perms(u64 gfn, enum kvm_pgtable_prot prot, struct pkvm_hyp_vcpu *vcpu); > > The parameters are the same as __pkvm_host_share_guest, but in a > different order. I looked ahead at later patches in the series, and similar > issues regarding parameter type and ordering, so I won't mention it > for the later patches. Ack to this and the other comment below, thanks for the review! > > > 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 04a9053ae1d5..60dd56bbd743 100644 > > --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c > > +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c > > @@ -267,6 +267,25 @@ static void handle___pkvm_host_unshare_guest(struct kvm_cpu_context *host_ctxt) > > cpu_reg(host_ctxt, 1) = ret; > > } > > > > +static void handle___pkvm_host_relax_guest_perms(struct kvm_cpu_context *host_ctxt) > > +{ > > + DECLARE_REG(u64, gfn, host_ctxt, 1); > > + DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 2); > > + struct pkvm_hyp_vcpu *hyp_vcpu; > > + int ret = -EINVAL; > > + > > + if (!is_protected_kvm_enabled()) > > + goto out; > > + > > + hyp_vcpu = pkvm_get_loaded_hyp_vcpu(); > > + if (!hyp_vcpu || pkvm_hyp_vcpu_is_protected(hyp_vcpu)) > > + goto out; > > + > > + ret = __pkvm_host_relax_guest_perms(gfn, prot, hyp_vcpu); > > +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); > > @@ -478,6 +497,7 @@ static const hcall_t host_hcall[] = { > > HANDLE_FUNC(__pkvm_host_unshare_hyp), > > HANDLE_FUNC(__pkvm_host_share_guest), > > HANDLE_FUNC(__pkvm_host_unshare_guest), > > + HANDLE_FUNC(__pkvm_host_relax_guest_perms), > > 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 aa27a3e42e5e..d4b28e93e790 100644 > > --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c > > +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c > > @@ -1480,3 +1480,26 @@ int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm) > > > > return ret; > > } > > + > > +int __pkvm_host_relax_guest_perms(u64 gfn, enum kvm_pgtable_prot prot, struct pkvm_hyp_vcpu *vcpu) > > +{ > > + struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu); > > + u64 ipa = hyp_pfn_to_phys(gfn); > > + u64 phys; > > + int ret; > > + > > + if ((prot & KVM_PGTABLE_PROT_RWX) != prot) > > + return -EPERM; > > Why not > > + if (prot & ~KVM_PGTABLE_PROT_RWX) > > Simpler and consistent with similar checks in the file (e.g., > __pkvm_host_share_guest) > > Cheers, > /fuad > > > > + > > + host_lock_component(); > > + guest_lock_component(vm); > > + > > + ret = __check_host_unshare_guest(vm, &phys, ipa); > > + if (!ret) > > + ret = kvm_pgtable_stage2_relax_perms(&vm->pgt, ipa, prot, 0); > > + > > + guest_unlock_component(vm); > > + host_unlock_component(); > > + > > + return ret; > > +} > > -- > > 2.47.0.338.g60cca15819-goog > >
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 0b6c4d325134..5d51933e44fb 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -67,6 +67,7 @@ enum __kvm_host_smccc_func { __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___pkvm_host_relax_guest_perms, __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 e528a42ed60e..db0dd83c2457 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -41,6 +41,7 @@ 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); +int __pkvm_host_relax_guest_perms(u64 gfn, enum kvm_pgtable_prot prot, struct pkvm_hyp_vcpu *vcpu); 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 04a9053ae1d5..60dd56bbd743 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -267,6 +267,25 @@ static void handle___pkvm_host_unshare_guest(struct kvm_cpu_context *host_ctxt) cpu_reg(host_ctxt, 1) = ret; } +static void handle___pkvm_host_relax_guest_perms(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(u64, gfn, host_ctxt, 1); + DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 2); + struct pkvm_hyp_vcpu *hyp_vcpu; + int ret = -EINVAL; + + if (!is_protected_kvm_enabled()) + goto out; + + hyp_vcpu = pkvm_get_loaded_hyp_vcpu(); + if (!hyp_vcpu || pkvm_hyp_vcpu_is_protected(hyp_vcpu)) + goto out; + + ret = __pkvm_host_relax_guest_perms(gfn, prot, hyp_vcpu); +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); @@ -478,6 +497,7 @@ static const hcall_t host_hcall[] = { HANDLE_FUNC(__pkvm_host_unshare_hyp), HANDLE_FUNC(__pkvm_host_share_guest), HANDLE_FUNC(__pkvm_host_unshare_guest), + HANDLE_FUNC(__pkvm_host_relax_guest_perms), 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 aa27a3e42e5e..d4b28e93e790 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -1480,3 +1480,26 @@ int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm) return ret; } + +int __pkvm_host_relax_guest_perms(u64 gfn, enum kvm_pgtable_prot prot, struct pkvm_hyp_vcpu *vcpu) +{ + struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu); + u64 ipa = hyp_pfn_to_phys(gfn); + u64 phys; + int ret; + + if ((prot & KVM_PGTABLE_PROT_RWX) != prot) + return -EPERM; + + host_lock_component(); + guest_lock_component(vm); + + ret = __check_host_unshare_guest(vm, &phys, ipa); + if (!ret) + ret = kvm_pgtable_stage2_relax_perms(&vm->pgt, ipa, prot, 0); + + guest_unlock_component(vm); + host_unlock_component(); + + return ret; +}
Introduce a new hypercall allowing the host to relax the stage-2 permissions of mappings in a non-protected guest page-table. It will be used later once we start allowing RO memslots and dirty logging. Signed-off-by: Quentin Perret <qperret@google.com> --- 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 | 20 ++++++++++++++++ arch/arm64/kvm/hyp/nvhe/mem_protect.c | 23 +++++++++++++++++++ 4 files changed, 45 insertions(+)