From 3a43970d55e9fd5475d3c4e5fe398ab831ec6c3a Mon Sep 17 00:00:00 2001 From: Sukadev Bhattiprolu Date: Mon, 6 Jan 2020 18:02:37 -0800 Subject: [PATCH] KVM: PPC: Book3S HV: Implement H_SVM_INIT_ABORT hcall Implement the H_SVM_INIT_ABORT hcall which the Ultravisor can use to abort an SVM after it has issued the H_SVM_INIT_START and before the H_SVM_INIT_DONE hcalls. This hcall could be used when Ultravisor encounters security violations or other errors when starting an SVM. Note that this hcall is different from UV_SVM_TERMINATE ucall which is used by HV to terminate/cleanup an VM that has becore secure. The H_SVM_INIT_ABORT basically undoes operations that were done since the H_SVM_INIT_START hcall - i.e page-out all the VM pages back to normal memory, and terminate the SVM. (If we do not bring the pages back to normal memory, the text/data of the VM would be stuck in secure memory and since the SVM did not go secure, its MSR_S bit will be clear and the VM wont be able to access its pages even to do a clean exit). Based on patches and discussion with Paul Mackerras, Ram Pai and Bharata Rao. Signed-off-by: Ram Pai Signed-off-by: Sukadev Bhattiprolu Signed-off-by: Bharata B Rao Signed-off-by: Paul Mackerras --- Documentation/powerpc/ultravisor.rst | 60 +++++++++++++++++++++ arch/powerpc/include/asm/hvcall.h | 1 + arch/powerpc/include/asm/kvm_book3s_uvmem.h | 6 +++ arch/powerpc/include/asm/kvm_host.h | 1 + arch/powerpc/kvm/book3s_hv.c | 3 ++ arch/powerpc/kvm/book3s_hv_uvmem.c | 28 ++++++++++ 6 files changed, 99 insertions(+) diff --git a/Documentation/powerpc/ultravisor.rst b/Documentation/powerpc/ultravisor.rst index 730854f73830..363736d7fd36 100644 --- a/Documentation/powerpc/ultravisor.rst +++ b/Documentation/powerpc/ultravisor.rst @@ -948,6 +948,66 @@ Use cases up its internal state for this virtual machine. +H_SVM_INIT_ABORT +---------------- + + Abort the process of securing an SVM. + +Syntax +~~~~~~ + +.. code-block:: c + + uint64_t hypercall(const uint64_t H_SVM_INIT_ABORT) + +Return values +~~~~~~~~~~~~~ + + One of the following values: + + * H_PARAMETER on successfully cleaning up the state, + Hypervisor will return this value to the + **guest**, to indicate that the underlying + UV_ESM ultracall failed. + + * H_STATE if called after a VM has gone secure (i.e + H_SVM_INIT_DONE hypercall was successful). + + * H_UNSUPPORTED if called from a wrong context (e.g. from a + normal VM). + +Description +~~~~~~~~~~~ + + Abort the process of securing a virtual machine. This call must + be made after a prior call to ``H_SVM_INIT_START`` hypercall and + before a call to ``H_SVM_INIT_DONE``. + + On entry into this hypercall the non-volatile GPRs and FPRs are + expected to contain the values they had at the time the VM issued + the UV_ESM ultracall. Further ``SRR0`` is expected to contain the + address of the instruction after the ``UV_ESM`` ultracall and ``SRR1`` + the MSR value with which to return to the VM. + + This hypercall will cleanup any partial state that was established for + the VM since the prior ``H_SVM_INIT_START`` hypercall, including paging + out pages that were paged-into secure memory, and issue the + ``UV_SVM_TERMINATE`` ultracall to terminate the VM. + + After the partial state is cleaned up, control returns to the VM + (**not Ultravisor**), at the address specified in ``SRR0`` with the + MSR values set to the value in ``SRR1``. + +Use cases +~~~~~~~~~ + + If after a successful call to ``H_SVM_INIT_START``, the Ultravisor + encounters an error while securing a virtual machine, either due + to lack of resources or because the VM's security information could + not be validated, Ultravisor informs the Hypervisor about it. + Hypervisor should use this call to clean up any internal state for + this virtual machine and return to the VM. + H_SVM_PAGE_IN ------------- diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h index 13bd870609c3..e90c073e437e 100644 --- a/arch/powerpc/include/asm/hvcall.h +++ b/arch/powerpc/include/asm/hvcall.h @@ -350,6 +350,7 @@ #define H_SVM_PAGE_OUT 0xEF04 #define H_SVM_INIT_START 0xEF08 #define H_SVM_INIT_DONE 0xEF0C +#define H_SVM_INIT_ABORT 0xEF14 /* Values for 2nd argument to H_SET_MODE */ #define H_SET_MODE_RESOURCE_SET_CIABR 1 diff --git a/arch/powerpc/include/asm/kvm_book3s_uvmem.h b/arch/powerpc/include/asm/kvm_book3s_uvmem.h index 3cf8425b9838..5a9834e0e2d1 100644 --- a/arch/powerpc/include/asm/kvm_book3s_uvmem.h +++ b/arch/powerpc/include/asm/kvm_book3s_uvmem.h @@ -19,6 +19,7 @@ unsigned long kvmppc_h_svm_page_out(struct kvm *kvm, unsigned long kvmppc_h_svm_init_start(struct kvm *kvm); unsigned long kvmppc_h_svm_init_done(struct kvm *kvm); int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn); +unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm); void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free, struct kvm *kvm, bool skip_page_out); #else @@ -62,6 +63,11 @@ static inline unsigned long kvmppc_h_svm_init_done(struct kvm *kvm) return H_UNSUPPORTED; } +static inline unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm) +{ + return H_UNSUPPORTED; +} + static inline int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn) { return -EFAULT; diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 0a398f2321c2..6e8b8ffd06ad 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -278,6 +278,7 @@ struct kvm_resize_hpt; /* Flag values for kvm_arch.secure_guest */ #define KVMPPC_SECURE_INIT_START 0x1 /* H_SVM_INIT_START has been called */ #define KVMPPC_SECURE_INIT_DONE 0x2 /* H_SVM_INIT_DONE completed */ +#define KVMPPC_SECURE_INIT_ABORT 0x4 /* H_SVM_INIT_ABORT issued */ struct kvm_arch { unsigned int lpid; diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 47ffc7f1b104..1118cff7f7ef 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -1091,6 +1091,9 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu) case H_SVM_INIT_DONE: ret = kvmppc_h_svm_init_done(vcpu->kvm); break; + case H_SVM_INIT_ABORT: + ret = kvmppc_h_svm_init_abort(vcpu->kvm); + break; default: return RESUME_HOST; diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c index ffa602a97dba..4d1f25a3959a 100644 --- a/arch/powerpc/kvm/book3s_hv_uvmem.c +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c @@ -286,6 +286,34 @@ void kvmppc_uvmem_drop_pages(const struct kvm_memory_slot *free, } } +unsigned long kvmppc_h_svm_init_abort(struct kvm *kvm) +{ + int srcu_idx; + struct kvm_memory_slot *memslot; + + /* + * Expect to be called only after INIT_START and before INIT_DONE. + * If INIT_DONE was completed, use normal VM termination sequence. + */ + if (!(kvm->arch.secure_guest & KVMPPC_SECURE_INIT_START)) + return H_UNSUPPORTED; + + if (kvm->arch.secure_guest & KVMPPC_SECURE_INIT_DONE) + return H_STATE; + + srcu_idx = srcu_read_lock(&kvm->srcu); + + kvm_for_each_memslot(memslot, kvm_memslots(kvm)) + kvmppc_uvmem_drop_pages(memslot, kvm, false); + + srcu_read_unlock(&kvm->srcu, srcu_idx); + + kvm->arch.secure_guest = 0; + uv_svm_terminate(kvm->arch.lpid); + + return H_PARAMETER; +} + /* * Get a free device PFN from the pool * -- 2.20.1