From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from theia.8bytes.org (8bytes.org [81.169.241.247]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 500972FB7 for ; Thu, 10 Jun 2021 09:12:06 +0000 (UTC) Received: from cap.home.8bytes.org (p4ff2ba7c.dip0.t-ipconnect.de [79.242.186.124]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by theia.8bytes.org (Postfix) with ESMTPSA id C434E4B7; Thu, 10 Jun 2021 11:11:57 +0200 (CEST) From: Joerg Roedel To: x86@kernel.org Cc: Joerg Roedel , Joerg Roedel , hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , David Rientjes , Cfir Cohen , Erdem Aktas , Masami Hiramatsu , Mike Stunes , Sean Christopherson , Martin Radev , Arvind Sankar , linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: [PATCH v4 5/6] x86/insn: Extend error reporting from insn_fetch_from_user[_inatomic]() Date: Thu, 10 Jun 2021 11:11:40 +0200 Message-Id: <20210610091141.30322-6-joro@8bytes.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210610091141.30322-1-joro@8bytes.org> References: <20210610091141.30322-1-joro@8bytes.org> X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Joerg Roedel The error reporting from the insn_fetch_from_user*() functions is not very verbose. Extend it to include information on whether the linear RIP could not be calculated or whether the memory access faulted. This will be used in the SEV-ES code to propagate the correct exception depending on what went wrong during instruction fetch. Signed-off-by: Joerg Roedel --- arch/x86/kernel/sev.c | 8 ++++---- arch/x86/kernel/umip.c | 10 ++++------ arch/x86/lib/insn-eval.c | 8 ++++++-- 3 files changed, 14 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 475bbc1b3547..a7045a5a94ca 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -267,17 +267,17 @@ static int vc_fetch_insn_kernel(struct es_em_ctxt *ctxt, static enum es_result __vc_decode_user_insn(struct es_em_ctxt *ctxt) { char buffer[MAX_INSN_SIZE]; - int res; + int insn_bytes; - res = insn_fetch_from_user_inatomic(ctxt->regs, buffer); - if (!res) { + insn_bytes = insn_fetch_from_user_inatomic(ctxt->regs, buffer); + if (insn_bytes <= 0) { ctxt->fi.vector = X86_TRAP_PF; ctxt->fi.error_code = X86_PF_INSTR | X86_PF_USER; ctxt->fi.cr2 = ctxt->regs->ip; return ES_EXCEPTION; } - if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, res)) + if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, insn_bytes)) return ES_DECODE_FAILED; if (ctxt->insn.immediate.got) diff --git a/arch/x86/kernel/umip.c b/arch/x86/kernel/umip.c index 8daa70b0d2da..337178809c89 100644 --- a/arch/x86/kernel/umip.c +++ b/arch/x86/kernel/umip.c @@ -346,14 +346,12 @@ bool fixup_umip_exception(struct pt_regs *regs) if (!regs) return false; - nr_copied = insn_fetch_from_user(regs, buf); - /* - * The insn_fetch_from_user above could have failed if user code - * is protected by a memory protection key. Give up on emulation - * in such a case. Should we issue a page fault? + * Give up on emulation if fetching the instruction failed. Should we + * issue a page fault or a #GP? */ - if (!nr_copied) + nr_copied = insn_fetch_from_user(regs, buf); + if (nr_copied <= 0) return false; if (!insn_decode_from_regs(&insn, regs, buf, nr_copied)) diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index 4eecb9c7c6a0..1b5cdf8b7a4e 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -1451,6 +1451,8 @@ static int insn_get_effective_ip(struct pt_regs *regs, unsigned long *ip) * Number of instruction bytes copied. * * 0 if nothing was copied. + * + * -EINVAL if the linear address of the instruction could not be calculated */ int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) { @@ -1458,7 +1460,7 @@ int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) int not_copied; if (insn_get_effective_ip(regs, &ip)) - return 0; + return -EINVAL; not_copied = copy_from_user(buf, (void __user *)ip, MAX_INSN_SIZE); @@ -1479,6 +1481,8 @@ int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) * Number of instruction bytes copied. * * 0 if nothing was copied. + * + * -EINVAL if the linear address of the instruction could not be calculated */ int insn_fetch_from_user_inatomic(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) { @@ -1486,7 +1490,7 @@ int insn_fetch_from_user_inatomic(struct pt_regs *regs, unsigned char buf[MAX_IN int not_copied; if (insn_get_effective_ip(regs, &ip)) - return 0; + return -EINVAL; not_copied = __copy_from_user_inatomic(buf, (void __user *)ip, MAX_INSN_SIZE); -- 2.31.1 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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6CF59C49EA3 for ; Thu, 10 Jun 2021 09:12:07 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2EC6E613F5 for ; Thu, 10 Jun 2021 09:12:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2EC6E613F5 Authentication-Results: mail.kernel.org; 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Thu, 10 Jun 2021 09:12:02 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id E162283D0C for ; Thu, 10 Jun 2021 09:12:01 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 4qsrlH0KBx6U for ; Thu, 10 Jun 2021 09:12:01 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from theia.8bytes.org (8bytes.org [81.169.241.247]) by smtp1.osuosl.org (Postfix) with ESMTPS id 0F9EE83D1B for ; Thu, 10 Jun 2021 09:12:00 +0000 (UTC) Received: from cap.home.8bytes.org (p4ff2ba7c.dip0.t-ipconnect.de [79.242.186.124]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by theia.8bytes.org (Postfix) with ESMTPSA id C434E4B7; Thu, 10 Jun 2021 11:11:57 +0200 (CEST) From: Joerg Roedel To: x86@kernel.org Subject: [PATCH v4 5/6] x86/insn: Extend error reporting from insn_fetch_from_user[_inatomic]() Date: Thu, 10 Jun 2021 11:11:40 +0200 Message-Id: <20210610091141.30322-6-joro@8bytes.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210610091141.30322-1-joro@8bytes.org> References: <20210610091141.30322-1-joro@8bytes.org> MIME-Version: 1.0 Cc: kvm@vger.kernel.org, Peter Zijlstra , Dave Hansen , virtualization@lists.linux-foundation.org, Arvind Sankar , hpa@zytor.com, Jiri Slaby , Joerg Roedel , David Rientjes , Martin Radev , Tom Lendacky , Joerg Roedel , Kees Cook , Cfir Cohen , linux-coco@lists.linux.dev, Andy Lutomirski , Dan Williams , Juergen Gross , Mike Stunes , Sean Christopherson , linux-kernel@vger.kernel.org, Masami Hiramatsu , Erdem Aktas X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" From: Joerg Roedel The error reporting from the insn_fetch_from_user*() functions is not very verbose. Extend it to include information on whether the linear RIP could not be calculated or whether the memory access faulted. This will be used in the SEV-ES code to propagate the correct exception depending on what went wrong during instruction fetch. Signed-off-by: Joerg Roedel --- arch/x86/kernel/sev.c | 8 ++++---- arch/x86/kernel/umip.c | 10 ++++------ arch/x86/lib/insn-eval.c | 8 ++++++-- 3 files changed, 14 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 475bbc1b3547..a7045a5a94ca 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -267,17 +267,17 @@ static int vc_fetch_insn_kernel(struct es_em_ctxt *ctxt, static enum es_result __vc_decode_user_insn(struct es_em_ctxt *ctxt) { char buffer[MAX_INSN_SIZE]; - int res; + int insn_bytes; - res = insn_fetch_from_user_inatomic(ctxt->regs, buffer); - if (!res) { + insn_bytes = insn_fetch_from_user_inatomic(ctxt->regs, buffer); + if (insn_bytes <= 0) { ctxt->fi.vector = X86_TRAP_PF; ctxt->fi.error_code = X86_PF_INSTR | X86_PF_USER; ctxt->fi.cr2 = ctxt->regs->ip; return ES_EXCEPTION; } - if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, res)) + if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, insn_bytes)) return ES_DECODE_FAILED; if (ctxt->insn.immediate.got) diff --git a/arch/x86/kernel/umip.c b/arch/x86/kernel/umip.c index 8daa70b0d2da..337178809c89 100644 --- a/arch/x86/kernel/umip.c +++ b/arch/x86/kernel/umip.c @@ -346,14 +346,12 @@ bool fixup_umip_exception(struct pt_regs *regs) if (!regs) return false; - nr_copied = insn_fetch_from_user(regs, buf); - /* - * The insn_fetch_from_user above could have failed if user code - * is protected by a memory protection key. Give up on emulation - * in such a case. Should we issue a page fault? + * Give up on emulation if fetching the instruction failed. Should we + * issue a page fault or a #GP? */ - if (!nr_copied) + nr_copied = insn_fetch_from_user(regs, buf); + if (nr_copied <= 0) return false; if (!insn_decode_from_regs(&insn, regs, buf, nr_copied)) diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index 4eecb9c7c6a0..1b5cdf8b7a4e 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -1451,6 +1451,8 @@ static int insn_get_effective_ip(struct pt_regs *regs, unsigned long *ip) * Number of instruction bytes copied. * * 0 if nothing was copied. + * + * -EINVAL if the linear address of the instruction could not be calculated */ int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) { @@ -1458,7 +1460,7 @@ int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) int not_copied; if (insn_get_effective_ip(regs, &ip)) - return 0; + return -EINVAL; not_copied = copy_from_user(buf, (void __user *)ip, MAX_INSN_SIZE); @@ -1479,6 +1481,8 @@ int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) * Number of instruction bytes copied. * * 0 if nothing was copied. + * + * -EINVAL if the linear address of the instruction could not be calculated */ int insn_fetch_from_user_inatomic(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) { @@ -1486,7 +1490,7 @@ int insn_fetch_from_user_inatomic(struct pt_regs *regs, unsigned char buf[MAX_IN int not_copied; if (insn_get_effective_ip(regs, &ip)) - return 0; + return -EINVAL; not_copied = __copy_from_user_inatomic(buf, (void __user *)ip, MAX_INSN_SIZE); -- 2.31.1 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization