| Message ID | 20241203103735.2267589-14-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 to remove the write permission from a > non-protected guest stage-2 mapping. This will be used for e.g. enabling > 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 | 24 +++++++++++++++++++ > arch/arm64/kvm/hyp/nvhe/mem_protect.c | 19 +++++++++++++++ > 4 files changed, 45 insertions(+) > > diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h > index 5d51933e44fb..4d7d20ea03df 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_guest_perms, > + __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 db0dd83c2457..8658b5932473 100644 > --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h > +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h > @@ -42,6 +42,7 @@ 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); > +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 60dd56bbd743..3feaf2119e51 100644 > --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c > +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c > @@ -286,6 +286,29 @@ static void handle___pkvm_host_relax_guest_perms(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_pkvm_hyp_vm(handle); > + if (!hyp_vm) > + goto out; > + if (pkvm_hyp_vm_is_protected(hyp_vm)) > + goto put_hyp_vm; These checks are (unsurprisingly) the same for all these functions. Does it make sense to have a helper do these checks? Cheers, /fuad > + ret = __pkvm_host_wrprotect_guest(gfn, hyp_vm); > +put_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); > @@ -498,6 +521,7 @@ static const hcall_t host_hcall[] = { > HANDLE_FUNC(__pkvm_host_share_guest), > HANDLE_FUNC(__pkvm_host_unshare_guest), > HANDLE_FUNC(__pkvm_host_relax_guest_perms), > + 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 d4b28e93e790..89312d7cde2a 100644 > --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c > +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c > @@ -1503,3 +1503,22 @@ int __pkvm_host_relax_guest_perms(u64 gfn, enum kvm_pgtable_prot prot, struct pk > > 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_unshare_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; > +} > -- > 2.47.0.338.g60cca15819-goog >
On Tuesday 10 Dec 2024 at 15:06:53 (+0000), Fuad Tabba wrote: > > +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_pkvm_hyp_vm(handle); > > + if (!hyp_vm) > > + goto out; > > + if (pkvm_hyp_vm_is_protected(hyp_vm)) > > + goto put_hyp_vm; > > These checks are (unsurprisingly) the same for all these functions. > Does it make sense to have a helper do these checks? Yup, that makes sense and should simplify the error handling on all the call sites. I'll probably call that get_np_pkvm_hyp_vm() or something along those lines and shove in pkvm.c in v3.
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 5d51933e44fb..4d7d20ea03df 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_guest_perms, + __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 db0dd83c2457..8658b5932473 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -42,6 +42,7 @@ 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); +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 60dd56bbd743..3feaf2119e51 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -286,6 +286,29 @@ static void handle___pkvm_host_relax_guest_perms(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_pkvm_hyp_vm(handle); + if (!hyp_vm) + goto out; + if (pkvm_hyp_vm_is_protected(hyp_vm)) + goto put_hyp_vm; + + ret = __pkvm_host_wrprotect_guest(gfn, hyp_vm); +put_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); @@ -498,6 +521,7 @@ static const hcall_t host_hcall[] = { HANDLE_FUNC(__pkvm_host_share_guest), HANDLE_FUNC(__pkvm_host_unshare_guest), HANDLE_FUNC(__pkvm_host_relax_guest_perms), + 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 d4b28e93e790..89312d7cde2a 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -1503,3 +1503,22 @@ int __pkvm_host_relax_guest_perms(u64 gfn, enum kvm_pgtable_prot prot, struct pk 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_unshare_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; +}
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. 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 | 24 +++++++++++++++++++ arch/arm64/kvm/hyp/nvhe/mem_protect.c | 19 +++++++++++++++ 4 files changed, 45 insertions(+)