From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0AB2DC3A5A7 for ; Wed, 7 Dec 2022 01:02:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229662AbiLGBCY (ORCPT ); Tue, 6 Dec 2022 20:02:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57350 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229448AbiLGBCW (ORCPT ); Tue, 6 Dec 2022 20:02:22 -0500 Received: from mail-pj1-x104a.google.com (mail-pj1-x104a.google.com [IPv6:2607:f8b0:4864:20::104a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D29754EC1E for ; Tue, 6 Dec 2022 17:02:20 -0800 (PST) Received: by mail-pj1-x104a.google.com with SMTP id o18-20020a17090aac1200b00219ca917708so7254692pjq.8 for ; Tue, 06 Dec 2022 17:02:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=CMPVlgS6pxpUcA8VfsiIl4y+WqNXbQ8tMsHTw45HE5M=; b=jIJi1SrPO4NwswTp8ZLHA7dBiWHzZ4KDFjaZmeJD8k4jldzLl+btAcOTtDLvzNF8m3 fd0Qvy/9R0IaY/gSqAS9UI/PUQJkF3gk7lUDUgnM5DmucgV50sLwKbsjglVh2ln8ggcx HboxZghEWujvk0PP+61UwVagxk3lRVa+eJzo9hVKVWLfWaZqFxk8kcFw+WHPd9KR33XT hz3jIxFRB7IbyC35113dJTh0M1/naMdVWyePMODppx90CqZCtdRPICH43l95O+xotzzJ QZdQjQ8ZCnnHOb/Js52UEY5iTqD8wIAyktu3qDNl6ZL1SHHda9fNVl/T9EguKtahxngv w2+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=CMPVlgS6pxpUcA8VfsiIl4y+WqNXbQ8tMsHTw45HE5M=; b=V5Hyn1weBfd3cXbVjyH+FUU3L98Z9xkFBXECvrtmIdhUvuUTDkDYaE/BhvjpcZ5b3T V09slC3BxOKgTFY0wsUC/JyzjHBGSjwhToBxRojDBlqVzGgSg0C30JEL5L3aqmOZb2qG QoZ2Wln8PciwUbJBeaRROv/UiAs6OOFQzRk0bAZjeG2OmOGtw7g4XtkRLvP3ppdnVsXL msezf2qaoL0bbl2FxKJjohamT2jgVmIN/6SwMMNF796lX+qYTA4KRkxINFMvbWMlev18 DSCzp4fvXJSLWL9tvko6WwFAIxMatzY7/bCiEK1j22p4MWO+v+YFk9b5hJFAriPPeHmX CGqA== X-Gm-Message-State: ANoB5plgqA3Hgh97ux/XzoOPxYd0dc7twGCuDi0k9pNPaAtJw5V+pw2v fKHp5UJrrmbR8NsfCvNYpggPgMl5n0atUyj9V/JOaiIHCswu0yDGl8f1BdwYZfX7g9RnUunkthI aAldgRjv63EIoFNWa2ojajDet576bmXetTUIIGXS1mcUnjCn1H8MKtACmp0rF2DJ+IlgiqcR7Q6 MmnrWVeVY= X-Google-Smtp-Source: AA0mqf493bvVRsnknvS/YnaKOWmNWZAMmrqTmsY+gcvWsu3GB4COSqdka2Z7aPpZkrNlRP2GHKVWJZoLeQr7QXMGOQ== X-Received: from dionnaglaze.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2ee6]) (user=dionnaglaze job=sendgmr) by 2002:a05:6a00:2396:b0:572:698b:5fa9 with SMTP id f22-20020a056a00239600b00572698b5fa9mr70619809pfc.28.1670374940234; Tue, 06 Dec 2022 17:02:20 -0800 (PST) Date: Wed, 7 Dec 2022 01:02:06 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.39.0.rc0.267.gcb52ba06e7-goog Message-ID: <20221207010210.2563293-1-dionnaglaze@google.com> Subject: [PATCH v9 0/4] Add throttling detection to sev-guest From: Dionna Glaze To: linux-kernel@vger.kernel.org, x86@kernel.org Cc: Dionna Glaze , Tom Lendacky , Paolo Bonzini , Joerg Roedel , Peter Gonda , Thomas Gleixner , Dave Hansen , Borislav Petkov Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The guest request synchronous API from SEV-SNP VMs to the host's security processor consumes a global resource. For this reason, AMD's docs recommend that the host implements a throttling mechanism. In order for the guest to know it's been throttled and should try its request again, we need some good-faith communication from the host that the request has been throttled. These patches work with the existing /dev/sev-guest ABI to detect a throttling code. Changes from v8: * Added documentation changes. * Changed commit messages to use passive voice. * Simplified control flow for __sev_platform_init_locked. Changes from v7: * Replaced handle_guest_request arguments msg_ver and fw_err with a pointer to the snp_guest_request_ioctl argument struct. Changes from v6: * Rebased on the IV reuse fix patch * renamed rate_hz to rate_s and fixed its MODULE_PARM_DESC to use the correct variable name. * Changed sleep_timeout_interrutible (not defined) to schedule_timeout_interruptible. Changes from v5: * Fixed commit prefix text * Added all get_maintainers.pl folks to commits' Cc tags * Changed SET_RET_NO_FW_CALL commit's metadata to show pgonda signs off and is the author. Changes from v4: * Clarified comment on SEV_RET_NO_FW_CALL * Changed ratelimit loop to use sleep_timeout_interruptible Changes from v3: * sev-guest ratelimits itself to one request twice a second. * Fixed a type signature to use u64 instead of unsigned int * Set *exitinfo2 unconditionally after the ghcb_hv_call. Changes from v2: * Codified the non-firmware-call firmware error code as (u32)-1. * Changed sev_issue_guest_request unsigned long *fw_err argument to u64 *exitinfo2 to more accurately and type-safely describe the value that it outputs. * Changed sev_issue_guest_request to always set its exitinfo2 argument to either the non-firmware-call error code, the EXIT_INFO_2 returned from the VMM if the request failed, or 0 on success. This fixes a bug that returned uninitialized kernel stack memory to the user when there is no error. * Changed the throttle behavior to retry in the driver instead of returning -EAGAIN, due to possible message sequence number reuse on different message contents. Changes from v1: * Changed throttle error code to 2 Cc: Tom Lendacky Cc: Paolo Bonzini Cc: Joerg Roedel Cc: Peter Gonda Cc: Thomas Gleixner Cc: Dave Hansen Cc: Borislav Petkov Signed-off-by: Dionna Glaze Dionna Glaze (3): x86/sev: Change snp_guest_issue_request's fw_err virt: sev-guest: Remove err in handle_guest_request virt: sev-guest: interpret VMM errors from guest request Peter Gonda (1): crypto: ccp - Name -1 return value as SEV_RET_NO_FW_CALL Documentation/virt/coco/sev-guest.rst | 21 ++++--- arch/x86/include/asm/sev.h | 4 +- arch/x86/kernel/sev.c | 10 ++-- drivers/crypto/ccp/sev-dev.c | 22 ++++--- drivers/virt/coco/sev-guest/sev-guest.c | 76 +++++++++++++++++-------- include/uapi/linux/psp-sev.h | 7 +++ include/uapi/linux/sev-guest.h | 18 +++++- 7 files changed, 112 insertions(+), 46 deletions(-) -- 2.39.0.rc0.267.gcb52ba06e7-goog