From patchwork Mon Jun 12 07:47:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vasant Karasulli X-Patchwork-Id: 13275734 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 3157DC7EE25 for ; Mon, 12 Jun 2023 07:50:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235485AbjFLHud (ORCPT ); Mon, 12 Jun 2023 03:50:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236078AbjFLHtw (ORCPT ); Mon, 12 Jun 2023 03:49:52 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D401CCE for ; Mon, 12 Jun 2023 00:49:20 -0700 (PDT) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 013E42048E; Mon, 12 Jun 2023 07:48:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1686556096; 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=fRvJwkdfvdP/6bmTGpHx3R+bAAEzjogT73pCJKfoseE=; b=zmAgazrLKaNKtksPvEc854cEwNZJ4DxrJtj878aptIRPrdrSNbI6mlK0wslqbzOkrwnw5D 6kz4BGNbmE5m7EqGc/lczCYOWQoBJswJPYExgNG+SfvdQSIGwRWBg3K8Qm3RlawaghnY6R lYYjhvdbkBh106ZDlp+bpCFAW9SwVSE= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1686556096; 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=fRvJwkdfvdP/6bmTGpHx3R+bAAEzjogT73pCJKfoseE=; b=q21BKO6T7xFGLk7YbYjeKdSUpA0TVNOk+oZQLKeATCrn6pMkjNo9U/fzI1bLpjDV1xbC6N TiB+nteU34qVW3CA== Received: from vasant-suse.fritz.box (unknown [10.163.24.134]) by relay2.suse.de (Postfix) with ESMTP id 965072C142; Mon, 12 Jun 2023 07:48:15 +0000 (UTC) From: Vasant Karasulli To: pbonzini@redhat.com Cc: Thomas.Lendacky@amd.com, drjones@redhat.com, erdemaktas@google.com, jroedel@suse.de, kvm@vger.kernel.org, marcorr@google.com, rientjes@google.com, seanjc@google.com, zxwang42@gmail.com, Vasant Karasulli , Varad Gautam Subject: [PATCH v4 06/11] x86: AMD SEV-ES: Prepare for #VC processing Date: Mon, 12 Jun 2023 09:47:53 +0200 Message-Id: <20230612074758.9177-7-vkarasulli@suse.de> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230612074758.9177-1-vkarasulli@suse.de> References: <20230612074758.9177-1-vkarasulli@suse.de> 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 6d7d0603ca7c397a07efc88e314e38b4242a3a8d. Signed-off-by: Varad Gautam Signed-off-by: Vasant Karasulli --- lib/x86/amd_sev_vc.c | 87 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) diff --git a/lib/x86/amd_sev_vc.c b/lib/x86/amd_sev_vc.c index f622703..1eefaf0 100644 --- a/lib/x86/amd_sev_vc.c +++ b/lib/x86/amd_sev_vc.c @@ -1,15 +1,102 @@ // SPDX-License-Identifier: GPL-2.0 +/* + * AMD SEV-ES #VC exception handling. + * Adapted from Linux@6d7d0603ca: + * - arch/x86/kernel/sev.c + * - arch/x86/kernel/sev-shared.c + */ #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; }