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[2620:137:e000::1:20]) by mx.google.com with ESMTP id ja3-20020a170902efc300b001870feba7a1si14830829plb.135.2022.11.02.18.13.02; Wed, 02 Nov 2022 18:13:14 -0700 (PDT) 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=FB7DqmA0; 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 S230132AbiKCBKr (ORCPT + 99 others); Wed, 2 Nov 2022 21:10:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229459AbiKCBKp (ORCPT ); Wed, 2 Nov 2022 21:10:45 -0400 Received: from mail-pj1-x1049.google.com (mail-pj1-x1049.google.com [IPv6:2607:f8b0:4864:20::1049]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1736B5FBD for ; Wed, 2 Nov 2022 18:10:45 -0700 (PDT) Received: by mail-pj1-x1049.google.com with SMTP id m1-20020a17090a5a4100b002138550729dso95959pji.2 for ; Wed, 02 Nov 2022 18:10:45 -0700 (PDT) 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=Mx+leU/OWscSldITB3zFpjjWetd6P6K/f9rRzitMlcU=; b=FB7DqmA0EsKuQjHGYVy6dlGV3LQmMHrxbEDBmyNUCU0nLo9tWvbXVXq2p8EX9pt5RT L0AZX85Pyhm88hzJOo+TL3Tj2ZSVpPOluVWzkIn7h2G02+a8vLAPujhjqpOOkEb2eI8T 082tPzndK3fvZ5dOL53kZpS/0v/UB6PROEdVvpRhxQxSIBMViXPwm/B9+bBI9Wb6kk/n 0VZ/kr8PlIErWquySXarbqhYBrWDHG1PF7JYhgSGQ2pvUpOkGXGUVTf/lm8WIDMP35gz Rkn+3dbPmgzAMuxH7fqTBjfdMZteVDG0d17wQgqn9UW3BxHQSnUUL/f6Q6QFt0q0kMyY Hbfg== 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=Mx+leU/OWscSldITB3zFpjjWetd6P6K/f9rRzitMlcU=; b=VCj6qlRCL41NsxJxFf+oqoSOx8A3YkelKI3m2V8njQo6svYiZ3uZHghQ2Day1BfIWn 1QMwLqxT7XPiTl/iVG/ZgxnU+Dy6wMLAgR+VxzjOx+f8fS8/rqq2/g4hIgCnRg9+QmLz zkPV1bn1iWw7gyKMCkcOdQqEeonPnqWqjFbBxOi0DsgtEA49GBCdeDw0M8xYPIQKfwaQ Y4V3qxND2Nryg/5Ff5gVZWbJnMomCGmT+A4GTo6kFuHaQbwXHNpV7ZDA0cLualExs3k1 Wk2VyzNicExiSZVkKPp9afov4xrSK1f8+5gsWpsBHfSzk1RopEsnCRww7nSQ2bgi2G9g MMQQ== X-Gm-Message-State: ACrzQf30Xgei5AwLztGonazBScnsBdPfFicJVNVXaQuvTPyRPyEYexxK uH26Rn1FqrcVvwARY3F35eRh7Wjhr+LDrR+7xVSK9+DXFyiTX/UokVumHgDW7QEEYXEqkppeI88 0cJFKqJX4NFwesY/TxIfuFpshE915TW4KWYUxAK8tRjmJK9KDdfxoWAdaEFvZX8gJu1576pjZdz gCEdoMRdg= X-Received: from dionnaglaze.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2ee6]) (user=dionnaglaze job=sendgmr) by 2002:a17:90b:3901:b0:213:dfd5:a75f with SMTP id ob1-20020a17090b390100b00213dfd5a75fmr19732129pjb.233.1667437844445; Wed, 02 Nov 2022 18:10:44 -0700 (PDT) Date: Thu, 3 Nov 2022 01:10:34 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.38.1.273.g43a17bfeac-goog Message-ID: <20221103011038.1542614-1-dionnaglaze@google.com> Subject: [PATCH v6 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 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?1748398159632190896?= X-GMAIL-MSGID: =?utf-8?q?1748435463041411652?= 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 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 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 arch/x86/include/asm/sev.h | 4 +- arch/x86/kernel/sev.c | 10 +++-- drivers/crypto/ccp/sev-dev.c | 2 +- drivers/virt/coco/sev-guest/sev-guest.c | 57 ++++++++++++++++++++----- include/uapi/linux/psp-sev.h | 7 +++ include/uapi/linux/sev-guest.h | 18 +++++++- 6 files changed, 78 insertions(+), 20 deletions(-)