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Tue, 7 Jan 2020 02:02:39 +0000 (GMT) Received: from b03ledav001.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0F9286E04E; Tue, 7 Jan 2020 02:02:38 +0000 (GMT) Received: from suka-w540.localdomain (unknown [9.70.94.45]) by b03ledav001.gho.boulder.ibm.com (Postfix) with ESMTP; Tue, 7 Jan 2020 02:02:38 +0000 (GMT) Received: by suka-w540.localdomain (Postfix, from userid 1000) id 64C672E0EE6; Mon, 6 Jan 2020 18:02:37 -0800 (PST) Date: Mon, 6 Jan 2020 18:02:37 -0800 From: Sukadev Bhattiprolu To: Ram Pai Cc: Sukadev Bhattiprolu , Michael Ellerman , Paul Mackerras , bharata@linux.ibm.com, linuxppc-dev@ozlabs.org, kvm-ppc@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v4 2/2] KVM: PPC: Implement H_SVM_INIT_ABORT hcall Message-ID: <20200107020237.GA29843@us.ibm.com> References: <20191219215146.27278-1-sukadev@linux.ibm.com> <20191219215146.27278-2-sukadev@linux.ibm.com> <20200103203712.GG5556@oc0525413822.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200103203712.GG5556@oc0525413822.ibm.com> X-Operating-System: Linux 2.0.32 on an i486 User-Agent: Mutt/1.10.1 (2018-07-13) X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2020-01-06_08:2020-01-06,2020-01-06 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 phishscore=0 malwarescore=0 lowpriorityscore=0 bulkscore=0 clxscore=1015 impostorscore=0 mlxlogscore=999 spamscore=0 mlxscore=0 priorityscore=1501 suspectscore=2 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-2001070014 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Ram Pai [linuxram@us.ibm.com] wrote: > > One small comment.. H_STATE is a better return code than H_UNSUPPORTED. > Here is the updated patch - we now return H_STATE if the abort call is made after the VM has gone secure. --- >From 73fe1fa5aff2829f2fae6a339169e56dc0bbae06 Mon Sep 17 00:00:00 2001 From: Sukadev Bhattiprolu Date: Fri, 27 Sep 2019 14:30:36 -0500 Subject: [PATCH 2/2] KVM: PPC: 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 should basically undo 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 --- Changelog[v4]: - [Bharata Rao] Add missing rcu locking - [Paul Mackerras] simplify code that walks memslots - Add a check to ensure that H_SVM_INIT_ABORT is called before H_SVM_INIT_DONE hcall (i.e the SVM is not already secure). - [Ram Pai] Return H_STATE if hcall is called after *INIT_DONE. Changelog[v3]: - Rather than pass the NIP/MSR as parameters, load them into SRR0/SRR1 (like we do with other registers) and terminate the VM after paging out pages - Move the code to add a skip_page_out parameter into a separate patch. Changelog[v2]: [Paul Mackerras] avoid returning to UV "one last time" after the state is cleaned up. So, we now have H_SVM_INIT_ABORT: - take the VM's NIP/MSR register states as parameters - inherit the state of other registers as at UV_ESM call. After cleaning up the partial state, HV uses these to return directly to the VM with a failed UV_ESM call. --- 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 577ca95fac7c..8310c0407383 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 66d5312be16b..1b22f2c7ad1b 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -1099,6 +1099,9 @@ 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 9a5bbad7d87e..522b57be0d45 100644 --- a/arch/powerpc/kvm/book3s_hv_uvmem.c +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c @@ -287,6 +287,34 @@ 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 * -- 2.17.2