From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brijesh Singh Subject: [RFC PATCH v2 29/32] kvm: svm: Add support for SEV DEBUG_DECRYPT command Date: Thu, 2 Mar 2017 10:18:17 -0500 Message-ID: <148846789744.2349.167641684941925238.stgit@brijesh-build-machine> References: <148846752022.2349.13667498174822419498.stgit@brijesh-build-machine> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <148846752022.2349.13667498174822419498.stgit@brijesh-build-machine> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: "devel" To: simon.guinot@sequanux.org, linux-efi@vger.kernel.org, brijesh.singh@amd.com, kvm@vger.kernel.org, rkrcmar@redhat.com, matt@codeblueprint.co.uk, linux-pci@vger.kernel.org, linus.walleij@linaro.org, gary.hook@amd.com, linux-mm@kvack.org, paul.gortmaker@windriver.com, hpa@zytor.com, cl@linux.com, dan.j.williams@intel.com, aarcange@redhat.com, sfr@canb.auug.org.au, andriy.shevchenko@linux.intel.com, herbert@gondor.apana.org.au, bhe@redhat.com, xemul@parallels.com, joro@8bytes.org, x86@kernel.org, peterz@infradead.org, piotr.luc@intel.com, mingo@redhat.com, msalter@redhat.com, ross.zwisler@linux.intel.com, bp@suse.de, dyoung@redhat.com, thomas.lendacky@amd.com, jroedel@suse.de, keescook@chromium.org, arnd@arndb.de, toshi.kani@hpe.com, mathieu.desnoyers@efficios.com, luto@kernel.org, devel@linuxdriverpro List-Id: linux-efi@vger.kernel.org The command is used to decrypt guest memory region for debug purposes. Signed-off-by: Brijesh Singh --- arch/x86/kvm/svm.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 977aa22..ce8819a 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -5986,6 +5986,78 @@ static int sev_guest_status(struct kvm *kvm, struct kvm_sev_cmd *argp) return ret; } +static int __sev_dbg_decrypt_page(struct kvm *kvm, unsigned long src, + void *dst, int *error) +{ + int ret; + struct page **inpages; + struct sev_data_dbg *data; + unsigned long npages; + + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + inpages = sev_pin_memory(src, PAGE_SIZE, &npages); + if (!inpages) { + ret = -ENOMEM; + goto err_1; + } + + data->handle = sev_get_handle(kvm); + data->dst_addr = __psp_pa(dst); + data->src_addr = __sev_page_pa(inpages[0]); + data->length = PAGE_SIZE; + + ret = sev_issue_cmd(kvm, SEV_CMD_DBG_DECRYPT, data, error); + if (ret) + printk(KERN_ERR "SEV: DEBUG_DECRYPT %d (%#010x)\n", + ret, *error); + sev_unpin_memory(inpages, npages); +err_1: + kfree(data); + return ret; +} + +static int sev_dbg_decrypt(struct kvm *kvm, struct kvm_sev_cmd *argp) +{ + void *data; + int ret, offset, len; + struct kvm_sev_dbg debug; + + if (!sev_guest(kvm)) + return -ENOTTY; + + if (copy_from_user(&debug, (void *)argp->data, + sizeof(struct kvm_sev_dbg))) + return -EFAULT; + /* + * TODO: add support for decrypting length which crosses the + * page boundary. + */ + offset = debug.src_addr & (PAGE_SIZE - 1); + if (offset + debug.length > PAGE_SIZE) + return -EINVAL; + + data = (void *) get_zeroed_page(GFP_KERNEL); + if (!data) + return -ENOMEM; + + /* decrypt full page */ + ret = __sev_dbg_decrypt_page(kvm, debug.src_addr & PAGE_MASK, + data, &argp->error); + if (ret) + goto err_1; + + /* we have decrypted full page but copy request length */ + len = min_t(size_t, (PAGE_SIZE - offset), debug.length); + if (copy_to_user((uint8_t *)debug.dst_addr, data + offset, len)) + ret = -EFAULT; +err_1: + free_page((unsigned long)data); + return ret; +} + static int amd_memory_encryption_cmd(struct kvm *kvm, void __user *argp) { int r = -ENOTTY; @@ -6013,6 +6085,10 @@ static int amd_memory_encryption_cmd(struct kvm *kvm, void __user *argp) r = sev_guest_status(kvm, &sev_cmd); break; } + case KVM_SEV_DBG_DECRYPT: { + r = sev_dbg_decrypt(kvm, &sev_cmd); + break; + } default: break; }