From patchwork Mon Feb 20 13:02:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeremi Piotrowski X-Patchwork-Id: 59445 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:eb09:0:0:0:0:0 with SMTP id s9csp1304124wrn; Mon, 20 Feb 2023 05:23:47 -0800 (PST) X-Google-Smtp-Source: AK7set+fwCoQcwvlv+yXjib6iyKK27EMfN/mURdMfoc+T42z+DrgBvJAEu84dWXUlpugcbHwn+Ej X-Received: by 2002:a05:6a20:3d8a:b0:c7:8d9b:1ebe with SMTP id s10-20020a056a203d8a00b000c78d9b1ebemr1652404pzi.14.1676899427166; Mon, 20 Feb 2023 05:23:47 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1676899427; cv=none; d=google.com; s=arc-20160816; b=ix01bGISudv+Ug7WYyFUj+fKFGn0ES17Xr1XvXVNKnlR2UQUFAHO0Ybgo/FWK131vC yY3TSB8MA797fB6qWopncFQK3BpgBvUfrfKdBChJQJz/LTVjZP9A3FXHXJLGPi+OZPnX uv2sExdA811pw8U5qbF1FVlYq5pcplD3s7Pg9GaleX/+cnxTgqlvSVBcb+EKm91gqMBS VCwcrhc1FsvCtkgk/XPUAKBEpwuIOTu0ywh9hd8Bq0Y6qPMEKHM3ulsDNMXhaB6g14Od fV/xfGlMzPS9qslBwo1iUaI+qnGKy5Do5buKSQc2/8A3FKCctDQbqbhe3v3sMymql1LG HtBQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :message-id:date:subject:cc:to:from:dkim-signature:dkim-filter; bh=U1TEgC//qrS3upr0HOqpecLJ2Ei13B1/WGBub5prWr0=; b=1FDE2JyP/zCVHL4oLqg39qW+Ml8OR5r4TiDiRqa+wgVnml/27/FWRsMB9JWRlL9T0H XY3fXLgsax5B6YIfW/qou346xalAppy18bB2bXoZftm/S5+EW+8mwlG9ipxSTYnYv4Iv tHfTpPrfnbaCvuW7JQbb7aYINHkXrJ6UPuCCScKCNDphzto2ZZ6j1rFuzyL+fK9Dgrv3 X+RlKE+U+CPObp4sg+FebskK/GuB14KsuuyWLkm0YVeMa54bxiPl8/Y90UEvKjzZjMct poOcmsq2kOiqfRLUS1WIVZzxy5KIYKP8v0BtXdx0kRVgIn1IWBLA3aJZvSv13w6FW0MK KqCw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linux.microsoft.com header.s=default header.b=enrwxpZb; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linux.microsoft.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id 11-20020a63060b000000b004ff90bed041si3462739pgg.415.2023.02.20.05.23.35; Mon, 20 Feb 2023 05:23:47 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linux.microsoft.com header.s=default header.b=enrwxpZb; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linux.microsoft.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231951AbjBTNCz (ORCPT + 99 others); Mon, 20 Feb 2023 08:02:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230107AbjBTNCy (ORCPT ); Mon, 20 Feb 2023 08:02:54 -0500 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 4A07A270D; Mon, 20 Feb 2023 05:02:53 -0800 (PST) Received: from vm02.corp.microsoft.com (unknown [167.220.196.155]) by linux.microsoft.com (Postfix) with ESMTPSA id ADC5C209A88D; Mon, 20 Feb 2023 05:02:51 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com ADC5C209A88D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1676898172; bh=U1TEgC//qrS3upr0HOqpecLJ2Ei13B1/WGBub5prWr0=; h=From:To:Cc:Subject:Date:From; b=enrwxpZbFqagIZ3T2LYJq+e43kievalPtz+BVBCZjO/Uz1skU0rO9Fw2YDB+R4NDx pbI0HchgBwxea+0dcSVbQQGoRgg0/8VhT1s+q/vxt6mwTj9kpY3G5ATDaJZr2ye+Dr fDkKtsm8Ks1o88t3TrEco7TwT30VMqwuNvrDzCqo= From: Jeremi Piotrowski To: linux-kernel@vger.kernel.org Cc: Jeremi Piotrowski , netdev@vger.kernel.org, Richard Cochran , Christoph Hellwig Subject: [PATCH] ptp: kvm: Use decrypted memory in confidential guest on x86 Date: Mon, 20 Feb 2023 13:02:35 +0000 Message-Id: <20230220130235.2603366-1-jpiotrowski@linux.microsoft.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Spam-Status: No, score=-19.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,ENV_AND_HDR_SPF_MATCH,RCVD_IN_DNSWL_MED, SPF_HELO_PASS,SPF_PASS,USER_IN_DEF_DKIM_WL,USER_IN_DEF_SPF_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1758356493900073129?= X-GMAIL-MSGID: =?utf-8?q?1758356493900073129?= KVM_HC_CLOCK_PAIRING currently fails inside SEV-SNP guests because the guest passes an address to static data to the host. In confidential computing the host can't access arbitrary guest memory so handling the hypercall runs into an "rmpfault". To make the hypercall work, the guest needs to explicitly mark the memory as decrypted. Do that in kvm_arch_ptp_init(), but retain the previous behavior for non-confidential guests to save us from having to allocate memory when not needed. Add a new arch-specific function (kvm_arch_ptp_exit()) to free the allocation and mark the memory as encrypted again. Signed-off-by: Jeremi Piotrowski --- Hi, I would love to not allocate a whole page just for this driver, swiotlb is decrypted but I don't have access to a 'struct device' here. Does anyone have any suggestion? Jeremi drivers/ptp/ptp_kvm_arm.c | 4 +++ drivers/ptp/ptp_kvm_common.c | 1 + drivers/ptp/ptp_kvm_x86.c | 59 +++++++++++++++++++++++++++++------- 3 files changed, 53 insertions(+), 11 deletions(-) diff --git a/drivers/ptp/ptp_kvm_arm.c b/drivers/ptp/ptp_kvm_arm.c index b7d28c8dfb84..e68e6943167b 100644 --- a/drivers/ptp/ptp_kvm_arm.c +++ b/drivers/ptp/ptp_kvm_arm.c @@ -22,6 +22,10 @@ int kvm_arch_ptp_init(void) return 0; } +void kvm_arch_ptp_exit(void) +{ +} + int kvm_arch_ptp_get_clock(struct timespec64 *ts) { return kvm_arch_ptp_get_crosststamp(NULL, ts, NULL); diff --git a/drivers/ptp/ptp_kvm_common.c b/drivers/ptp/ptp_kvm_common.c index 9141162c4237..2418977989be 100644 --- a/drivers/ptp/ptp_kvm_common.c +++ b/drivers/ptp/ptp_kvm_common.c @@ -130,6 +130,7 @@ static struct kvm_ptp_clock kvm_ptp_clock; static void __exit ptp_kvm_exit(void) { ptp_clock_unregister(kvm_ptp_clock.ptp_clock); + kvm_arch_ptp_exit(); } static int __init ptp_kvm_init(void) diff --git a/drivers/ptp/ptp_kvm_x86.c b/drivers/ptp/ptp_kvm_x86.c index 4991054a2135..902844cc1a17 100644 --- a/drivers/ptp/ptp_kvm_x86.c +++ b/drivers/ptp/ptp_kvm_x86.c @@ -14,27 +14,64 @@ #include #include #include +#include static phys_addr_t clock_pair_gpa; -static struct kvm_clock_pairing clock_pair; +static struct kvm_clock_pairing clock_pair_glbl; +static struct kvm_clock_pairing *clock_pair; int kvm_arch_ptp_init(void) { + struct page *p; long ret; if (!kvm_para_available()) return -ENODEV; - clock_pair_gpa = slow_virt_to_phys(&clock_pair); - if (!pvclock_get_pvti_cpu0_va()) - return -ENODEV; + if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) { + p = alloc_page(GFP_KERNEL | __GFP_ZERO); + if (!p) + return -ENOMEM; + + clock_pair = page_address(p); + ret = set_memory_decrypted((unsigned long)clock_pair, 1); + if (ret) { + __free_page(p); + clock_pair = NULL; + goto nofree; + } + } else { + clock_pair = &clock_pair_glbl; + } + + clock_pair_gpa = slow_virt_to_phys(clock_pair); + if (!pvclock_get_pvti_cpu0_va()) { + ret = -ENODEV; + goto err; + } ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa, KVM_CLOCK_PAIRING_WALLCLOCK); - if (ret == -KVM_ENOSYS) - return -ENODEV; + if (ret == -KVM_ENOSYS) { + ret = -ENODEV; + goto err; + } return ret; + +err: + kvm_arch_ptp_exit(); +nofree: + return ret; +} + +void kvm_arch_ptp_exit(void) +{ + if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) { + WARN_ON(set_memory_encrypted((unsigned long)clock_pair, 1)); + free_page((unsigned long)clock_pair); + clock_pair = NULL; + } } int kvm_arch_ptp_get_clock(struct timespec64 *ts) @@ -49,8 +86,8 @@ int kvm_arch_ptp_get_clock(struct timespec64 *ts) return -EOPNOTSUPP; } - ts->tv_sec = clock_pair.sec; - ts->tv_nsec = clock_pair.nsec; + ts->tv_sec = clock_pair->sec; + ts->tv_nsec = clock_pair->nsec; return 0; } @@ -81,9 +118,9 @@ int kvm_arch_ptp_get_crosststamp(u64 *cycle, struct timespec64 *tspec, pr_err_ratelimited("clock pairing hypercall ret %lu\n", ret); return -EOPNOTSUPP; } - tspec->tv_sec = clock_pair.sec; - tspec->tv_nsec = clock_pair.nsec; - *cycle = __pvclock_read_cycles(src, clock_pair.tsc); + tspec->tv_sec = clock_pair->sec; + tspec->tv_nsec = clock_pair->nsec; + *cycle = __pvclock_read_cycles(src, clock_pair->tsc); } while (pvclock_read_retry(src, version)); *cs = &kvm_clock;