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=unavailable 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 48107C48BDF for ; Fri, 18 Jun 2021 11:54:27 +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 02187613E9 for ; Fri, 18 Jun 2021 11:54:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 02187613E9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=8bytes.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=virtualization-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id B3C90839BC; Fri, 18 Jun 2021 11:54:26 +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 syZRdhIYWuoZ; Fri, 18 Jun 2021 11:54:25 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp1.osuosl.org (Postfix) with ESMTPS id 469A58397F; Fri, 18 Jun 2021 11:54:25 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id F25ACC000D; Fri, 18 Jun 2021 11:54:24 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 4C3C9C000B for ; Fri, 18 Jun 2021 11:54:23 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 2D6DC605E3 for ; Fri, 18 Jun 2021 11:54:23 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id vQci4qb-kcq7 for ; Fri, 18 Jun 2021 11:54:21 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from theia.8bytes.org (8bytes.org [81.169.241.247]) by smtp3.osuosl.org (Postfix) with ESMTPS id 6E442605E0 for ; Fri, 18 Jun 2021 11:54:21 +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 DF7473A7; Fri, 18 Jun 2021 13:54:17 +0200 (CEST) From: Joerg Roedel To: x86@kernel.org Subject: [PATCH v7 1/2] x86/sev: Make sure IRQs are disabled while GHCB is active Date: Fri, 18 Jun 2021 13:54:08 +0200 Message-Id: <20210618115409.22735-2-joro@8bytes.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210618115409.22735-1-joro@8bytes.org> References: <20210618115409.22735-1-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 #VC handler only cares about IRQs being disabled while the GHCB is active, as it must not be interrupted by something which could cause another #VC while it holds the GHCB (NMI is the exception for which the backup GHCB exits). Make sure nothing interrupts the code path while the GHCB is active by disabling IRQs in sev_es_get_ghcb() and restoring the previous irq state in sev_es_put_ghcb(). Signed-off-by: Joerg Roedel --- arch/x86/kernel/sev.c | 34 ++++++++++++++++++++++------------ 1 file changed, 22 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 8178db07a06a..9f32cbb773d9 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -12,7 +12,6 @@ #include /* For show_regs() */ #include #include -#include #include #include #include @@ -192,11 +191,19 @@ void noinstr __sev_es_ist_exit(void) this_cpu_write(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC], *(unsigned long *)ist); } -static __always_inline struct ghcb *sev_es_get_ghcb(struct ghcb_state *state) +/* + * Nothing shall interrupt this code path while holding the per-CPU + * GHCB. The backup GHCB is only for NMIs interrupting this path. + * + * Callers must disable local interrupts around it. + */ +static noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state) { struct sev_es_runtime_data *data; struct ghcb *ghcb; + WARN_ON(!irqs_disabled()); + data = this_cpu_read(runtime_data); ghcb = &data->ghcb_page; @@ -213,7 +220,9 @@ static __always_inline struct ghcb *sev_es_get_ghcb(struct ghcb_state *state) data->ghcb_active = false; data->backup_ghcb_active = false; + instrumentation_begin(); panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use"); + instrumentation_end(); } /* Mark backup_ghcb active before writing to it */ @@ -486,11 +495,13 @@ static enum es_result vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt /* Include code shared with pre-decompression boot stage */ #include "sev-shared.c" -static __always_inline void sev_es_put_ghcb(struct ghcb_state *state) +static noinstr void __sev_put_ghcb(struct ghcb_state *state) { struct sev_es_runtime_data *data; struct ghcb *ghcb; + WARN_ON(!irqs_disabled()); + data = this_cpu_read(runtime_data); ghcb = &data->ghcb_page; @@ -514,7 +525,7 @@ void noinstr __sev_es_nmi_complete(void) struct ghcb_state state; struct ghcb *ghcb; - ghcb = sev_es_get_ghcb(&state); + ghcb = __sev_get_ghcb(&state); vc_ghcb_invalidate(ghcb); ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_NMI_COMPLETE); @@ -524,7 +535,7 @@ void noinstr __sev_es_nmi_complete(void) sev_es_wr_ghcb_msr(__pa_nodebug(ghcb)); VMGEXIT(); - sev_es_put_ghcb(&state); + __sev_put_ghcb(&state); } static u64 get_jump_table_addr(void) @@ -536,7 +547,7 @@ static u64 get_jump_table_addr(void) local_irq_save(flags); - ghcb = sev_es_get_ghcb(&state); + ghcb = __sev_get_ghcb(&state); vc_ghcb_invalidate(ghcb); ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_JUMP_TABLE); @@ -550,7 +561,7 @@ static u64 get_jump_table_addr(void) ghcb_sw_exit_info_2_is_valid(ghcb)) ret = ghcb->save.sw_exit_info_2; - sev_es_put_ghcb(&state); + __sev_put_ghcb(&state); local_irq_restore(flags); @@ -675,7 +686,7 @@ static void sev_es_ap_hlt_loop(void) struct ghcb_state state; struct ghcb *ghcb; - ghcb = sev_es_get_ghcb(&state); + ghcb = __sev_get_ghcb(&state); while (true) { vc_ghcb_invalidate(ghcb); @@ -692,7 +703,7 @@ static void sev_es_ap_hlt_loop(void) break; } - sev_es_put_ghcb(&state); + __sev_put_ghcb(&state); } /* @@ -1351,7 +1362,6 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication) } irq_state = irqentry_nmi_enter(regs); - lockdep_assert_irqs_disabled(); instrumentation_begin(); /* @@ -1360,7 +1370,7 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication) * keep the IRQs disabled to protect us against concurrent TLB flushes. */ - ghcb = sev_es_get_ghcb(&state); + ghcb = __sev_get_ghcb(&state); vc_ghcb_invalidate(ghcb); result = vc_init_em_ctxt(&ctxt, regs, error_code); @@ -1368,7 +1378,7 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication) if (result == ES_OK) result = vc_handle_exitcode(&ctxt, ghcb, error_code); - sev_es_put_ghcb(&state); + __sev_put_ghcb(&state); /* Done - now check the result */ switch (result) { -- 2.31.1 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization