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 D3586C27C76 for ; Fri, 20 Jan 2023 21:52:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229722AbjATVwJ (ORCPT ); Fri, 20 Jan 2023 16:52:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229379AbjATVwH (ORCPT ); Fri, 20 Jan 2023 16:52:07 -0500 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CDD8280BB0 for ; Fri, 20 Jan 2023 13:52:06 -0800 (PST) Received: by mail-pl1-x649.google.com with SMTP id jc17-20020a17090325d100b00194dd8a6c27so2226462plb.17 for ; Fri, 20 Jan 2023 13:52:06 -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=YCPP50mHftdrkugDIMlvr2wVSqJJApexnFpETZnZzW0=; b=X2M3rLR8vE1RJwS+2TFg3bJfcAv1ZEiCKtOeRX3Sf4mSKLfxZ3t3KAPoklBYwfEcKI EmAsLcJ/hIo4heDlEs9welo47sawB/Eo0Vpv4d6Q/jZbJf90hzatyjqbrgpVXIo+ejbV fYDTz6zjP516fwJluTNzxdTQsnYI17CmNOg2gGS/6hcI23talU83VobSxbEItki7RTWj q9kz/sdP8N/8iOccbv26GYJz40n8ZJpbpisso2l1zFRPr2/4cyxLW3rUmidobVoJXFC+ cotAj2tx/1UjVOM/fUgd/EZCJPx5XDGoeC4b00ePABOpJVGS5iIuIqrsSv//QHbEw8sP klBw== 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=YCPP50mHftdrkugDIMlvr2wVSqJJApexnFpETZnZzW0=; b=W9ROEN/ZM9xxcuqS0ZsmBq1r4/Jm971caZc/OKJoXNK4pNg12myUnvwSKwAKQweVmY fvYvhhlRTUnW+GwB6N7lIivulawJLnungEwYvn9BmyE6sOCOgBHQR4oYtCdKnR2sRHwj X1GYn6G3uxitSIyhiYR7Y9JXPVqJr3aFWIfN71TELlJQFNiIho07uBojxtPeoPbCx3DJ zfsaQFZ+Cm6TIrKCjkGWZXNZdRzvEhDYC2Sfwb0+S8JYQq7ieX/332Ld3T5rfrSOEml1 FmirBIrSoobMROzckYG1niir4lakOFvuZHSSwygmUnNUa5Wi3frt5TEkR50Eaw4IzzW2 TGaw== X-Gm-Message-State: AFqh2kqQa+q4yt5K6iJkrjpmZ33DbtNjmQ2G5d9TxdaSdB4fMwZ0QCky 5ecMOuTiHgni9G4c5fy9OnlWIcliNuHHsms5Hw== X-Google-Smtp-Source: AMrXdXtv8orWqEiUIxO0YpcfUv4PPEQN1V5nRM+6ZfzbWGgCdEEYoc2uTbgZX9HHNdbeGovIKZN067GE15XoA5mWYw== X-Received: from dionnaglaze.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2ee6]) (user=dionnaglaze job=sendgmr) by 2002:a17:902:aa01:b0:194:4edf:b178 with SMTP id be1-20020a170902aa0100b001944edfb178mr1541674plb.4.1674251526054; Fri, 20 Jan 2023 13:52:06 -0800 (PST) Date: Fri, 20 Jan 2023 21:48:53 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.39.0.246.g2a6d74b583-goog Message-ID: <20230120214857.835931-1-dionnaglaze@google.com> Subject: [PATCH v12 0/3] Add throttling detection to sev-guest From: Dionna Glaze To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: Dionna Glaze 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 v11: * Squashed all type changing patches into 1 that modifies both sev-guest and x86/kernel/sev.c. * Removed fw_err field from sev-guest command struct (renamed exitinfo2). Changes from v10: * Added sev_guestreq_err_t typedef early in chain to change a signature acress x86/sev and virt/coco/sev-guest in a single change. This makes all patches build. I have 3 cleanup patches to change the type and subsequently remove the typedef. * Changed exitinfo2 initial undefined value back to 0xff since Thomas indicated that a firmware error is only 16 bits. Changes from v9: * Rebased on v6.2-rc3 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 Dionna Glaze (2): x86/sev: Change snp_guest_issue_request's fw_err 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-common.h | 3 - arch/x86/include/asm/sev.h | 4 +- arch/x86/kernel/sev.c | 13 +++-- drivers/crypto/ccp/sev-dev.c | 22 ++++--- drivers/virt/coco/sev-guest/sev-guest.c | 77 +++++++++++++++++-------- include/uapi/linux/psp-sev.h | 7 +++ include/uapi/linux/sev-guest.h | 18 +++++- 8 files changed, 114 insertions(+), 51 deletions(-) -- 2.39.0.246.g2a6d74b583-goog