From patchwork Wed Dec 7 01:02:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dionna Amalie Glaze X-Patchwork-Id: 30564 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:f944:0:0:0:0:0 with SMTP id q4csp3140704wrr; Tue, 6 Dec 2022 17:04:42 -0800 (PST) X-Google-Smtp-Source: AA0mqf5tqxgWDtf9Tr+jYfUG0NPrIEFYCDlUChhUDU0z50L+Tgm1IHVqP6wKs6Dvhj+s2h7SdKRT X-Received: by 2002:a63:ff0b:0:b0:477:362d:85d3 with SMTP id k11-20020a63ff0b000000b00477362d85d3mr63196130pgi.395.1670375082321; Tue, 06 Dec 2022 17:04:42 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1670375082; cv=none; d=google.com; s=arc-20160816; b=L9A1ZNfn6KslH5tAO52MtfHBzsHE7g39B5YNvbhWK0DncJ4shfwFMl730RKhyLHMv5 SCZ2creShHyMIiRYKGJnMWrNMpg/ufsj7cNxMaWnMkQDNwe0errnU9gwiJBAKC2xeUDD LBMCmIyFzVWRp706djkenIXUjbbA8K/U4RTTtBGb7Z84OmM36xw8BNG0LnR3FzG85Ahy EDuJZb+CoW17fkv8dbTKeUjNMlkUDM2y1SK8XKnFxIri/dIlYEuDzaMnm9hsQ0uKRd3l jPVvL0yaRxQdxWeD8bMO/qTP/OCg0hQSLiPTkHdYZgmbsG09eIk8/pabrNr+8bEhuINW 01qg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=Kq4nsNsu12aUA8GuDAR6Rk/S1sw8FFUkbgn/FDY4oJQ=; b=nfhi0VASuj9fHbbqMPWcKFx9XAobSKzPp1+ApwWQCKMIgpeLs7/Kn0ZzeEOU0QNYUF NoqaqsxmT3gsxBzt3vjwYzlM3bZCJUxEut2m7g0aHUVpVhxvO/wzoU0BU48ehD6cR92k 3tpVU2GwQorrOXhjE4wK1ptJBGlUlEzTFnk+8X/iP5ABJ8j2ae/ucjcmYPR6UWyiEwFA MSsbskRTXE5a73yW/TKaekf/yaB3TOd/7PhxayRccPAcTqO2EwbZVhFP83fYCcu90066 LKgdyoKlvG9SypYKOv9lGbgI7XBJRsUAk0pVQQ8jwQmBL9RjPvOjNV04qjdKsq0/YyKN /+Yw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b="jHhlxV/U"; 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=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id f10-20020a636a0a000000b004611cfaca6asi18638249pgc.381.2022.12.06.17.04.29; Tue, 06 Dec 2022 17:04:42 -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=@google.com header.s=20210112 header.b="jHhlxV/U"; 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=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229722AbiLGBCb (ORCPT + 99 others); Tue, 6 Dec 2022 20:02:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57414 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229684AbiLGBC2 (ORCPT ); Tue, 6 Dec 2022 20:02:28 -0500 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 574A44F18E for ; Tue, 6 Dec 2022 17:02:27 -0800 (PST) Received: by mail-pf1-x449.google.com with SMTP id d3-20020a056a0010c300b005728633819aso14053316pfu.8 for ; Tue, 06 Dec 2022 17:02:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=Kq4nsNsu12aUA8GuDAR6Rk/S1sw8FFUkbgn/FDY4oJQ=; b=jHhlxV/UdgCOLo3JvbhKjdSCPKfo+9YiKMvILOwzfOeo+1FL0arji+cdZXGjyGCoxB M36Mkfxno3gFNpEf4awKk+CQ6qVw/+bPB9N3JN7odi6kusKJ8pMqmLoTFH9hxcnRsdl6 lBG+/2HEsd9cwAnxSD2pSZT/LKUNUXn/GcXYbDPLpFZ8z8bk1r8bxD3gx9bszDl+gPst xRs8ai9nkPxFjAFwtWY2MqlhWQsLn7BG8YMcnELOd5ziGzib4Kj6KqCSf2NJOmwP2TOM 7PLlqgNyqF3z7iuoect4es25mOXHQeCRutMjntilg60uY0KsLhwrUTGi9uV+m0oaynkI UMkw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Kq4nsNsu12aUA8GuDAR6Rk/S1sw8FFUkbgn/FDY4oJQ=; b=l1oQkxw+lxtNXr+IRJHRULuLLCTFSSmmHVnrl1bGpjs+koHn9EqF6/uUzKzZCV0pxU 9/5Gy/TSjFM3W7Do8MKOtZFUDj9LbszNo3TSj1PzpVpy6Q0lVrDfDb+hXzg2MdY5Xh0N 2ksCcfDYywFULZ1SYPp6x1JlbvdxHE4HXf9v7dWcZ0mceBtQjUYH2LgjIFCuP1P5zeLU 1pqaJIiQ9Jh7BVq/KwvGzfdqY1/9hUA3Pqgu56J8d+f4GYY4ao25lpkzw2eu89wGGCJN 6mufmyHsgKXkJruhkUnQZyTJHWPWnJDx6ktF1Jf9QcsNWEk0Qj7ti9KGjpoXR1bfUcTY Lf3w== X-Gm-Message-State: ANoB5pl8sYUBV8jv7r5G2pHuPuhK+rVVFZ4UtwAI33azhnOlXCAebJ5H 6BN1w7EnCSnn/skFTC6t014qfmyed+Tu3kRPTdSFsgNaJ77M4KsIH5KKfEZubvKtuoPPgjVj3NH No9gnHEQXqt7NTpHW0P6PgrMNqyNMiSXGkZW+H4dTulg/3iK1EXNvi5e3GYPo4ooU/Pw+eH5uxj JpssOroQE= X-Received: from dionnaglaze.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2ee6]) (user=dionnaglaze job=sendgmr) by 2002:a05:6a00:1f0f:b0:56e:7424:bc0f with SMTP id be15-20020a056a001f0f00b0056e7424bc0fmr81486148pfb.11.1670374946793; Tue, 06 Dec 2022 17:02:26 -0800 (PST) Date: Wed, 7 Dec 2022 01:02:07 +0000 In-Reply-To: <20221207010210.2563293-1-dionnaglaze@google.com> Mime-Version: 1.0 References: <20221207010210.2563293-1-dionnaglaze@google.com> X-Mailer: git-send-email 2.39.0.rc0.267.gcb52ba06e7-goog Message-ID: <20221207010210.2563293-2-dionnaglaze@google.com> Subject: [PATCH v9 1/4] crypto: ccp - Name -1 return value as SEV_RET_NO_FW_CALL From: Dionna Glaze To: linux-kernel@vger.kernel.org, x86@kernel.org Cc: Peter Gonda , Thomas Lendacky , Paolo Bonzini , Joerg Roedel , Ingo Molnar , Andy Lutomirsky , John Allen , Herbert Xu , "David S. Miller" , Borislav Petkov , Dionna Glaze X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_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?1751515222118704023?= X-GMAIL-MSGID: =?utf-8?q?1751515222118704023?= From: Peter Gonda The PSP can return a "firmware error" code of -1 in circumstances where the PSP is not actually called. To make this protocol unambiguous, the value is named SEV_RET_NO_FW_CALL. Cc: Thomas Lendacky Cc: Paolo Bonzini Cc: Joerg Roedel Cc: Ingo Molnar Cc: Andy Lutomirsky Cc: John Allen Cc: Herbert Xu Cc: "David S. Miller" Cc: Borislav Petkov Signed-off-by: Peter Gonda Signed-off-by: Dionna Glaze Signed-off-by: Peter Gonda Signed-off-by: Dionna Glaze Signed-off-by: Borislav Petkov (AMD) Acked-by: Tom Lendacky --- Documentation/virt/coco/sev-guest.rst | 2 +- drivers/crypto/ccp/sev-dev.c | 22 ++++++++++++++-------- include/uapi/linux/psp-sev.h | 7 +++++++ 3 files changed, 22 insertions(+), 9 deletions(-) diff --git a/Documentation/virt/coco/sev-guest.rst b/Documentation/virt/coco/sev-guest.rst index bf593e88cfd9..e76393e389eb 100644 --- a/Documentation/virt/coco/sev-guest.rst +++ b/Documentation/virt/coco/sev-guest.rst @@ -41,7 +41,7 @@ The guest ioctl should be issued on a file descriptor of the /dev/sev-guest devi The ioctl accepts struct snp_user_guest_request. The input and output structure is specified through the req_data and resp_data field respectively. If the ioctl fails to execute due to a firmware error, then fw_err code will be set otherwise the -fw_err will be set to 0x00000000000000ff. +fw_err will be set to 0x00000000ffffffff, i.e., the lower 32-bits are -1. The firmware checks that the message sequence counter is one greater than the guests message sequence counter. If guest driver fails to increment message diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index 06fc7156c04f..ac205f78a595 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -440,12 +440,19 @@ static int __sev_init_ex_locked(int *error) return __sev_do_cmd_locked(SEV_CMD_INIT_EX, &data, error); } +static inline int __sev_do_init_locked(int *psp_ret) +{ + if (sev_init_ex_buffer) + return __sev_init_ex_locked(psp_ret); + else + return __sev_init_locked(psp_ret); +} + static int __sev_platform_init_locked(int *error) { struct psp_device *psp = psp_master; struct sev_device *sev; - int rc = 0, psp_ret = -1; - int (*init_function)(int *error); + int rc = 0, psp_ret = SEV_RET_NO_FW_CALL; if (!psp || !psp->sev_data) return -ENODEV; @@ -456,15 +463,12 @@ static int __sev_platform_init_locked(int *error) return 0; if (sev_init_ex_buffer) { - init_function = __sev_init_ex_locked; rc = sev_read_init_ex_file(); if (rc) return rc; - } else { - init_function = __sev_init_locked; } - rc = init_function(&psp_ret); + rc = __sev_do_init_locked(&psp_ret); if (rc && psp_ret == SEV_RET_SECURE_DATA_INVALID) { /* * Initialization command returned an integrity check failure @@ -473,9 +477,11 @@ static int __sev_platform_init_locked(int *error) * initialization function should succeed by replacing the state * with a reset state. */ - dev_err(sev->dev, "SEV: retrying INIT command because of SECURE_DATA_INVALID error. Retrying once to reset PSP SEV state."); - rc = init_function(&psp_ret); + dev_err(sev->dev, +"SEV: retrying INIT command because of SECURE_DATA_INVALID error. Retrying once to reset PSP SEV state."); + rc = __sev_do_init_locked(&psp_ret); } + if (error) *error = psp_ret; diff --git a/include/uapi/linux/psp-sev.h b/include/uapi/linux/psp-sev.h index 91b4c63d5cbf..e8cfb8bde0d7 100644 --- a/include/uapi/linux/psp-sev.h +++ b/include/uapi/linux/psp-sev.h @@ -36,6 +36,13 @@ enum { * SEV Firmware status code */ typedef enum { + /* + * This error code is not in the SEV spec but is added to convey that + * there was an error that prevented the SEV Firmware from being called. + * The SEV API error codes are 16 bits, so the -1 value will not overlap + * with possible values from the specification. + */ + SEV_RET_NO_FW_CALL = -1, SEV_RET_SUCCESS = 0, SEV_RET_INVALID_PLATFORM_STATE, SEV_RET_INVALID_GUEST_STATE, From patchwork Wed Dec 7 01:02:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dionna Amalie Glaze X-Patchwork-Id: 30565 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:f944:0:0:0:0:0 with SMTP id q4csp3140722wrr; Tue, 6 Dec 2022 17:04:46 -0800 (PST) X-Google-Smtp-Source: AA0mqf7ZbjDrwjlfMBK/l1TqMqA+VvO8oUlirIaN1qg8qmdApI+jLCftcvjlqYfmVhIpf/dNngjz X-Received: by 2002:a63:2251:0:b0:476:cb2a:b99b with SMTP id t17-20020a632251000000b00476cb2ab99bmr81237115pgm.436.1670375086206; Tue, 06 Dec 2022 17:04:46 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1670375086; cv=none; d=google.com; s=arc-20160816; b=tcTKABgc+yvVx3sZ8eJ6+WKQIPIIu9JO7P//TiKhFrU0rrMM9dO58nr1aORqYl1iKd 4Cjrwf7jJu5yZhk2eJEi/Wd8RRaqFsj7bube0RQotVna4VlCeIiCHjyPF6qTjetcFfty 52ilJ97gyk8eyHsaPiwUIWfnd4UfFSXAQUJQaop8lYal66bG3kyPm2uNmXr1K5tjRB8H /p7/r10TfOMnjVxUyHXLEqZrC6vAQ57WR1sNCvJasM/p8wzY8BJ5Fkf2VrdfphPycT0y JbHpuVnWLbT4yKdMHs/OyQLgyHq03WE/AtbRHplioMxT7TFKuR4+GZiWt3n4az0Ap9Rj sY9Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=GMGURl9LxXOJnwuiD/Ha/hCLoLpmM+oX4OEPqCyeymM=; b=WIxnrG1TLLvPi8lsG/C5cCF+9+yOdGZQoVvyjGSAHEPwYUlkQxqt+77lFN7NatLidk rTvkHQdwKlZXDn1WXPdXtgZmZyFGGNM3dHlw+KmStuvJ3Suj3Y6muvqOo3r4d2KpQjts MvIqS1WYUThf+tfEyjzjb2FEDO4fSDlNr2BSKPV3inq7/FiHLYDyaWTu89GuVEIXYCIV ubCXMvlKnLjC5M5KE1+EqqrOS+C67X59v4skgHjfZxowLSdY3/PMV5aDol+xJq79V3Mv w37nhBW1JecqALvaZC4rQRRGMCTkjyDCN91//cRRs3gKDx/QK1V1D9I8LNB/7/lws7xd NNMQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b=UnmJAc0+; 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=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. 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Peter Anvin" , Venu Busireddy , Michael Roth , "Kirill A. Shutemov" , Michael Sterritt X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_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?1751515226301942758?= X-GMAIL-MSGID: =?utf-8?q?1751515226301942758?= The GHCB specification declares that the firmware error value for a guest request will be stored in the lower 32 bits of EXIT_INFO_2. The upper 32 bits are for the VMM's own error code. The fw_err argument is thus a misnomer, and callers will need access to all 64 bits. The type of unsigned long also causes problems, since sw_exit_info2 is u64 (unsigned long long) vs the argument's previous unsigned long*. The signature change requires the follow-up change to drivers/virt/coco/sev-guest to use the new expected type in order to compile. The firmware might not even be called, so the call is bookended with the no firmware call error and clearing the error. Cc: Tom Lendacky Cc: Paolo Bonzini Cc: Joerg Roedel Cc: Peter Gonda Cc: Thomas Gleixner Cc: Dave Hansen Cc: Ingo Molnar Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Venu Busireddy Cc: Michael Roth Cc: "Kirill A. Shutemov" Cc: Michael Sterritt Fixes: d5af44dde546 ("x86/sev: Provide support for SNP guest request NAEs") Reviewed-by: Tom Lendacky Reviewed-by: Borislav Petkov Signed-off-by: Dionna Glaze --- arch/x86/include/asm/sev.h | 4 ++-- arch/x86/kernel/sev.c | 10 ++++++---- 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index ebc271bb6d8e..05de34d10d89 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -196,7 +196,7 @@ void snp_set_memory_private(unsigned long vaddr, unsigned int npages); void snp_set_wakeup_secondary_cpu(void); bool snp_init(struct boot_params *bp); void __init __noreturn snp_abort(void); -int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err); +int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, u64 *exitinfo2); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } @@ -217,7 +217,7 @@ static inline void snp_set_wakeup_secondary_cpu(void) { } static inline bool snp_init(struct boot_params *bp) { return false; } static inline void snp_abort(void) { } static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, - unsigned long *fw_err) + u64 *exitinfo2) { return -ENOTTY; } diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index a428c62330d3..148f17cb07b5 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include @@ -2175,7 +2176,7 @@ static int __init init_sev_config(char *str) } __setup("sev=", init_sev_config); -int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err) +int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, u64 *exitinfo2) { struct ghcb_state state; struct es_em_ctxt ctxt; @@ -2186,9 +2187,11 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) return -ENODEV; - if (!fw_err) + if (!exitinfo2) return -EINVAL; + *exitinfo2 = SEV_RET_NO_FW_CALL; + /* * __sev_get_ghcb() needs to run with IRQs disabled because it is using * a per-CPU GHCB. @@ -2212,14 +2215,13 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned if (ret) goto e_put; + *exitinfo2 = ghcb->save.sw_exit_info_2; if (ghcb->save.sw_exit_info_2) { /* Number of expected pages are returned in RBX */ if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST && ghcb->save.sw_exit_info_2 == SNP_GUEST_REQ_INVALID_LEN) input->data_npages = ghcb_get_rbx(ghcb); - *fw_err = ghcb->save.sw_exit_info_2; - ret = -EIO; } From patchwork Wed Dec 7 01:02:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dionna Amalie Glaze X-Patchwork-Id: 30566 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:f944:0:0:0:0:0 with SMTP id q4csp3141052wrr; Tue, 6 Dec 2022 17:05:31 -0800 (PST) X-Google-Smtp-Source: AA0mqf5zpjCsSLorDVeRkn168Iw3X3EuBP31HPVeMtiXa0sIgWF1N51kFCGbEhAV2vu6nbKTDrz+ X-Received: by 2002:a05:6a00:1bcb:b0:574:ba25:1e43 with SMTP id o11-20020a056a001bcb00b00574ba251e43mr56247429pfw.63.1670375131066; Tue, 06 Dec 2022 17:05:31 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1670375131; cv=none; d=google.com; s=arc-20160816; b=R9V6h+GyeqWUoCVmkd8lFJvO3WzuLcDHbfTxP+BRqX0fk8zpEAE9ZZwuPj1ZGDhx5k cbYidfUbdpr5Pps4GigiNaCdQ70bJr2aDZ5S31trLqScFrkKRmEw4prwvl1e+FTKHUDg UM+CZifcu5ZJpm/Ob67iQpGZCM9kf1GpjUCOnIUQe0BVGHSTPI3+1oNhr4huKQkMu5Ol HLwE2rzN6j8Ze2QXwt0rmRaOwEEIMDwp7daq7x7omxCRPTsK7cyeBiYt1UALIW8yDQad RdMtO3mkAtSVtKATrQqgZ2IxPy+jxrvkzBK9GYOHp6WlAl3SsqNX3g9/N3QN71+3uWYl 1bHg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=LYb5Kkl7KCSyA25o8WI4Ic+8SfxAdiy9vbY0soW+D/8=; b=VPqwMxMOf56jMMSb9EJAsltuUEuy7Q0QMAzfbT6kFhtc9rXpNuOUxr6n0o+lGz9cZG MAZ9ik+VyMZG7lK8qkUV4go8pCb9NbRyDTC4zjkvQ2qFrMpS4XQIvlzeaqgN0oj0fQ+E PcGyOTjKG0yyVchDRZq5gyjFDNvh/hv2m2Q6MY8XqnY8JjOiaSU4TO8f4ka1gL+p7tHf DkvXLohk6DDV8VuxQMX6+y4HMhP179zGIaKxAzTmz7KY3ph+u7q50xrteFpw0lOG4gp3 9RBz4pSZfHAkaFHDwQy+GF7CBazhyVUT+nnPM7dmgN2IIEKbwi/RZUcqpcrCCi2AVzJ+ XFmQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b=Pi2ZKrH8; 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=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. 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This is undefined behavior, and currently returns uninitialized kernel stack memory to user space. The fw_err argument is better to just pass through to snp_issue_guest_request, so that's done by passing along the ioctl argument. This removes the need for an argument to handle_guest_request. Cc: Tom Lendacky Cc: Paolo Bonzini Cc: Joerg Roedel Cc: Peter Gonda Cc: Thomas Gleixner Cc: Dave Hansen Cc: Borislav Petkov Cc: Haowen Bai Cc: Liam Merwick Cc: Yang Yingliang Fixes: fce96cf04430 ("virt: Add SEV-SNP guest driver") Reviewed-by: Tom Lendacky Signed-off-by: Dionna Glaze --- drivers/virt/coco/sev-guest/sev-guest.c | 35 ++++++++++++------------- 1 file changed, 17 insertions(+), 18 deletions(-) diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c index 1ea6d2e5b218..4a2a0a02985f 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -320,11 +320,11 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 return __enc_payload(snp_dev, req, payload, sz); } -static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, int msg_ver, +static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, + struct snp_guest_request_ioctl *arg, u8 type, void *req_buf, size_t req_sz, void *resp_buf, - u32 resp_sz, __u64 *fw_err) + u32 resp_sz) { - unsigned long err; u64 seqno; int rc; @@ -336,7 +336,8 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in memset(snp_dev->response, 0, sizeof(struct snp_guest_msg)); /* Encrypt the userspace provided payload */ - rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz); + rc = enc_payload(snp_dev, seqno, arg->msg_version, type, req_buf, + req_sz); if (rc) return rc; @@ -346,7 +347,8 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in * sequence number must be incremented or the VMPCK must be deleted to * prevent reuse of the IV. */ - rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err); + rc = snp_issue_guest_request(exit_code, &snp_dev->input, + &arg->fw_err); /* * If the extended guest request fails due to having too small of a @@ -368,24 +370,22 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in * of the VMPCK and the error code being propagated back to the * user as an ioctl() return code. */ - rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err); + rc = snp_issue_guest_request(exit_code, &snp_dev->input, + &arg->fw_err); /* * Override the error to inform callers the given extended * request buffer size was too small and give the caller the * required buffer size. */ - err = SNP_GUEST_REQ_INVALID_LEN; + arg->fw_err = SNP_GUEST_REQ_INVALID_LEN; snp_dev->input.data_npages = certs_npages; } - if (fw_err) - *fw_err = err; - if (rc) { dev_alert(snp_dev->dev, "Detected error from ASP request. rc: %d, fw_err: %llu\n", - rc, *fw_err); + rc, arg->fw_err); goto disable_vmpck; } @@ -432,9 +432,9 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io if (!resp) return -ENOMEM; - rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg->msg_version, + rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg, SNP_MSG_REPORT_REQ, &req, sizeof(req), resp->data, - resp_len, &arg->fw_err); + resp_len); if (rc) goto e_free; @@ -472,9 +472,8 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req))) return -EFAULT; - rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg->msg_version, - SNP_MSG_KEY_REQ, &req, sizeof(req), buf, resp_len, - &arg->fw_err); + rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg, + SNP_MSG_KEY_REQ, &req, sizeof(req), buf, resp_len); if (rc) return rc; @@ -534,9 +533,9 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques return -ENOMEM; snp_dev->input.data_npages = npages; - ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg->msg_version, + ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg, SNP_MSG_REPORT_REQ, &req.data, - sizeof(req.data), resp->data, resp_len, &arg->fw_err); + sizeof(req.data), resp->data, resp_len); /* If certs length is invalid then copy the returned length */ if (arg->fw_err == SNP_GUEST_REQ_INVALID_LEN) { From patchwork Wed Dec 7 01:02:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dionna Amalie Glaze X-Patchwork-Id: 30568 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:f944:0:0:0:0:0 with SMTP id q4csp3141270wrr; 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The sev-guest ABI has already locked in that the fw_err status of the input will be 64 bits, and that BIT_ULL(32) means that the extended guest request's data buffer was too small. Add BIT_ULL(33) for "host refused the request for throttling reasons". The driver interprets the upper 32 bits of exitinfo2 for the user anyway in case the request gets throttled. For safety, since the encryption algorithm in GHCBv2 is AES_GCM, control must remain in the kernel to complete the request with the current sequence number. Returning without finishing the request allows the the guest to make another request but with different message contents. This is IV reuse, and breaks cryptographic protections. When throttled, the driver will reschedule itself and then try again after sleeping half its ratelimit time to avoid a big wait queue. The ioctl may block indefinitely, but that has always been the case when deferring these requests to the host. Cc: Tom Lendacky Cc: Peter Gonda Cc: Borislav Petkov Cc: Tom Lendacky Cc: Liam Merwick Cc: Yang Yingliang Cc: Haowen Bai Reviewed-by: Tom Lendacky Signed-off-by: Dionna Glaze --- Documentation/virt/coco/sev-guest.rst | 21 +++++++---- drivers/virt/coco/sev-guest/sev-guest.c | 49 ++++++++++++++++++++----- include/uapi/linux/sev-guest.h | 18 ++++++++- 3 files changed, 70 insertions(+), 18 deletions(-) diff --git a/Documentation/virt/coco/sev-guest.rst b/Documentation/virt/coco/sev-guest.rst index e76393e389eb..fd8bf833f1cd 100644 --- a/Documentation/virt/coco/sev-guest.rst +++ b/Documentation/virt/coco/sev-guest.rst @@ -37,11 +37,12 @@ along with a description: the return value. General error numbers (-ENOMEM, -EINVAL) are not detailed, but errors with specific meanings are. -The guest ioctl should be issued on a file descriptor of the /dev/sev-guest device. -The ioctl accepts struct snp_user_guest_request. The input and output structure is -specified through the req_data and resp_data field respectively. If the ioctl fails -to execute due to a firmware error, then fw_err code will be set otherwise the -fw_err will be set to 0x00000000ffffffff, i.e., the lower 32-bits are -1. +The guest ioctl should be issued on a file descriptor of the +/dev/sev-guest device. The ioctl accepts struct +snp_user_guest_request. The input and output structure is specified +through the req_data and resp_data field respectively. If the ioctl +fails to execute due to a firmware error, then the fw_error code will +be set, otherwise fw_error will be set to -1. The firmware checks that the message sequence counter is one greater than the guests message sequence counter. If guest driver fails to increment message @@ -57,8 +58,14 @@ counter (e.g. counter overflow), then -EIO will be returned. __u64 req_data; __u64 resp_data; - /* firmware error code on failure (see psp-sev.h) */ - __u64 fw_err; + /* bits[63:32]: VMM error code, bits[31:0] firmware error code (see psp-sev.h) */ + union { + __u64 exitinfo2; + struct { + __u32 fw_error; + __u32 vmm_error; + }; + }; }; 2.1 SNP_GET_REPORT diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c index 4a2a0a02985f..6f62b90de4da 100644 --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -48,12 +49,22 @@ struct snp_guest_dev { struct snp_req_data input; u32 *os_area_msg_seqno; u8 *vmpck; + + struct ratelimit_state rs; }; static u32 vmpck_id; module_param(vmpck_id, uint, 0444); MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP."); +static int rate_s = 1; +module_param(rate_s, int, 0444); +MODULE_PARM_DESC(rate_s, "The rate limit interval in seconds to limit requests to."); + +static int rate_burst = 2; +module_param(rate_burst, int, 0444); +MODULE_PARM_DESC(rate_burst, "The rate limit burst amount to limit requests to."); + /* Mutex to serialize the shared buffer access and command handling. */ static DEFINE_MUTEX(snp_cmd_mutex); @@ -341,6 +352,16 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, if (rc) return rc; +retry: + /* + * Rate limit commands internally since the host can also throttle, and + * the guest shouldn't create a tight request spin that could end up + * getting this VM throttled more heavily. + */ + if (!__ratelimit(&snp_dev->rs)) { + schedule_timeout_interruptible((rate_s * HZ) / 2); + goto retry; + } /* * Call firmware to process the request. In this function the encrypted * message enters shared memory with the host. So after this call the @@ -348,7 +369,15 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, * prevent reuse of the IV. */ rc = snp_issue_guest_request(exit_code, &snp_dev->input, - &arg->fw_err); + &arg->exitinfo2); + + /* + * The host may return EBUSY if the request has been throttled. + * We retry in the driver to avoid returning and reusing the message + * sequence number on a different message. + */ + if (arg->vmm_error == SNP_GUEST_VMM_ERR_BUSY) + goto retry; /* * If the extended guest request fails due to having too small of a @@ -357,7 +386,7 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, * and thus avoid IV reuse. */ if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST && - err == SNP_GUEST_REQ_INVALID_LEN) { + arg->vmm_error == SNP_GUEST_VMM_ERR_INVALID_LEN) { const unsigned int certs_npages = snp_dev->input.data_npages; exit_code = SVM_VMGEXIT_GUEST_REQUEST; @@ -371,21 +400,21 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, * user as an ioctl() return code. */ rc = snp_issue_guest_request(exit_code, &snp_dev->input, - &arg->fw_err); + &arg->exitinfo2); /* * Override the error to inform callers the given extended * request buffer size was too small and give the caller the * required buffer size. */ - arg->fw_err = SNP_GUEST_REQ_INVALID_LEN; + arg->vmm_error = SNP_GUEST_VMM_ERR_INVALID_LEN; snp_dev->input.data_npages = certs_npages; } if (rc) { dev_alert(snp_dev->dev, - "Detected error from ASP request. rc: %d, fw_err: %llu\n", - rc, arg->fw_err); + "Detected error from ASP request. rc: %d, exitinfo2: %llu\n", + rc, arg->exitinfo2); goto disable_vmpck; } @@ -538,7 +567,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques sizeof(req.data), resp->data, resp_len); /* If certs length is invalid then copy the returned length */ - if (arg->fw_err == SNP_GUEST_REQ_INVALID_LEN) { + if (arg->vmm_error == SNP_GUEST_VMM_ERR_INVALID_LEN) { req.certs_len = snp_dev->input.data_npages << PAGE_SHIFT; if (copy_to_user((void __user *)arg->req_data, &req, sizeof(req))) @@ -573,7 +602,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long if (copy_from_user(&input, argp, sizeof(input))) return -EFAULT; - input.fw_err = 0xff; + input.exitinfo2 = SEV_RET_NO_FW_CALL; /* Message version must be non-zero */ if (!input.msg_version) @@ -604,7 +633,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long mutex_unlock(&snp_cmd_mutex); - if (input.fw_err && copy_to_user(argp, &input, sizeof(input))) + if (input.exitinfo2 && copy_to_user(argp, &input, sizeof(input))) return -EFAULT; return ret; @@ -754,6 +783,8 @@ static int __init sev_guest_probe(struct platform_device *pdev) if (ret) goto e_free_cert_data; + ratelimit_state_init(&snp_dev->rs, rate_s * HZ, rate_burst); + dev_info(dev, "Initialized SEV guest driver (using vmpck_id %d)\n", vmpck_id); return 0; diff --git a/include/uapi/linux/sev-guest.h b/include/uapi/linux/sev-guest.h index 256aaeff7e65..8e4144aa78c9 100644 --- a/include/uapi/linux/sev-guest.h +++ b/include/uapi/linux/sev-guest.h @@ -52,8 +52,15 @@ struct snp_guest_request_ioctl { __u64 req_data; __u64 resp_data; - /* firmware error code on failure (see psp-sev.h) */ - __u64 fw_err; + /* bits[63:32]: VMM error code, bits[31:0] firmware error code (see psp-sev.h) */ + union { + __u64 exitinfo2; + __u64 fw_err; /* Name deprecated in favor of others */ + struct { + __u32 fw_error; + __u32 vmm_error; + }; + }; }; struct snp_ext_report_req { @@ -77,4 +84,11 @@ struct snp_ext_report_req { /* Get SNP extended report as defined in the GHCB specification version 2. */ #define SNP_GET_EXT_REPORT _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x2, struct snp_guest_request_ioctl) +/* Guest message request EXIT_INFO_2 constants */ +#define SNP_GUEST_FW_ERR_MASK GENMASK_ULL(31, 0) +#define SNP_GUEST_VMM_ERR_SHIFT 32 + +#define SNP_GUEST_VMM_ERR_INVALID_LEN 1 +#define SNP_GUEST_VMM_ERR_BUSY 2 + #endif /* __UAPI_LINUX_SEV_GUEST_H_ */