From patchwork Thu Feb 24 10:54:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Varad Gautam X-Patchwork-Id: 12758337 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 96F6EC433FE for ; Thu, 24 Feb 2022 10:56:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233663AbiBXK4o (ORCPT ); Thu, 24 Feb 2022 05:56:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233652AbiBXK4j (ORCPT ); Thu, 24 Feb 2022 05:56:39 -0500 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 06AF127AFE9 for ; Thu, 24 Feb 2022 02:56:10 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id BC14B1F44C; Thu, 24 Feb 2022 10:56:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1645700168; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rdPgW9D5qO1ZDw5RZ4xe3ANsD+aWO1Y0zBt7bbA7tRU=; b=Tf/zLSsHelU1AgNvBg0Tkdzfqta3arJaj1nyh4v2pTWoR6dN4SL5pu2gTBWerOGZfCFZvj fFeYW9irzSRqhLRdk8yQ8ywhxqsFJoa3xvvOVvpCMZxH0CoOkKMB3Y236U1zteoOLi5SM7 lWBIXLNBswKcir3bvARP44Q0h2S1ywY= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 2FFAF13A79; Thu, 24 Feb 2022 10:56:08 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id KGakCUhkF2KYSgAAMHmgww (envelope-from ); Thu, 24 Feb 2022 10:56:08 +0000 From: Varad Gautam To: kvm@vger.kernel.org, pbonzini@redhat.com, drjones@redhat.com Cc: marcorr@google.com, zxwang42@gmail.com, erdemaktas@google.com, rientjes@google.com, seanjc@google.com, brijesh.singh@amd.com, Thomas.Lendacky@amd.com, jroedel@suse.de, bp@suse.de, varad.gautam@suse.com Subject: [kvm-unit-tests PATCH v3 06/11] x86: AMD SEV-ES: Prepare for #VC processing Date: Thu, 24 Feb 2022 11:54:46 +0100 Message-Id: <20220224105451.5035-7-varad.gautam@suse.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220224105451.5035-1-varad.gautam@suse.com> References: <20220224105451.5035-1-varad.gautam@suse.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Lay the groundwork for processing #VC exceptions in the handler. This includes clearing the GHCB, decoding the insn that triggered this #VC, and continuing execution after the exception has been processed. Based on Linux 64222515138e43da1fcf288f0289ef1020427b87. Signed-off-by: Varad Gautam --- lib/x86/amd_sev_vc.c | 90 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 89 insertions(+), 1 deletion(-) diff --git a/lib/x86/amd_sev_vc.c b/lib/x86/amd_sev_vc.c index 8226121..cbaf0c8 100644 --- a/lib/x86/amd_sev_vc.c +++ b/lib/x86/amd_sev_vc.c @@ -1,14 +1,102 @@ -/* SPDX-License-Identifier: GPL-2.0 */ +/* + * AMD SEV-ES #VC exception handling. + * Adapted from Linux@6422251513: + * - arch/x86/kernel/sev.c + * - arch/x86/kernel/sev-shared.c + * + * SPDX-License-Identifier: GPL-2.0 */ #include "amd_sev.h" +#include "svm.h" extern phys_addr_t ghcb_addr; +static void vc_ghcb_invalidate(struct ghcb *ghcb) +{ + ghcb->save.sw_exit_code = 0; + memset(ghcb->save.valid_bitmap, 0, sizeof(ghcb->save.valid_bitmap)); +} + +static bool vc_decoding_needed(unsigned long exit_code) +{ + /* Exceptions don't require to decode the instruction */ + return !(exit_code >= SVM_EXIT_EXCP_BASE && + exit_code <= SVM_EXIT_LAST_EXCP); +} + +static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt) +{ + unsigned char buffer[MAX_INSN_SIZE]; + int ret; + + memcpy(buffer, (unsigned char *)ctxt->regs->rip, MAX_INSN_SIZE); + + ret = insn_decode(&ctxt->insn, buffer, MAX_INSN_SIZE, INSN_MODE_64); + if (ret < 0) + return ES_DECODE_FAILED; + else + return ES_OK; +} + +static enum es_result vc_init_em_ctxt(struct es_em_ctxt *ctxt, + struct ex_regs *regs, + unsigned long exit_code) +{ + enum es_result ret = ES_OK; + + memset(ctxt, 0, sizeof(*ctxt)); + ctxt->regs = regs; + + if (vc_decoding_needed(exit_code)) + ret = vc_decode_insn(ctxt); + + return ret; +} + +static void vc_finish_insn(struct es_em_ctxt *ctxt) +{ + ctxt->regs->rip += ctxt->insn.length; +} + +static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt, + struct ghcb *ghcb, + unsigned long exit_code) +{ + enum es_result result; + + switch (exit_code) { + default: + /* + * Unexpected #VC exception + */ + result = ES_UNSUPPORTED; + } + + return result; +} + void handle_sev_es_vc(struct ex_regs *regs) { struct ghcb *ghcb = (struct ghcb *) ghcb_addr; + unsigned long exit_code = regs->error_code; + struct es_em_ctxt ctxt; + enum es_result result; + if (!ghcb) { /* TODO: kill guest */ return; } + + vc_ghcb_invalidate(ghcb); + result = vc_init_em_ctxt(&ctxt, regs, exit_code); + if (result == ES_OK) + result = vc_handle_exitcode(&ctxt, ghcb, exit_code); + if (result == ES_OK) { + vc_finish_insn(&ctxt); + } else { + printf("Unable to handle #VC exitcode, exit_code=%lx result=%x\n", + exit_code, result); + } + + return; }