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 43324C4743D for ; Tue, 8 Jun 2021 09:55:00 +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 05FE96124C for ; Tue, 8 Jun 2021 09:55:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 05FE96124C 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 DA3BA83A81; Tue, 8 Jun 2021 09:54:59 +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 di31BXcKNvNU; Tue, 8 Jun 2021 09:54:56 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp1.osuosl.org (Postfix) with ESMTP id 5BA9283143; Tue, 8 Jun 2021 09:54:55 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 3777AC000B; Tue, 8 Jun 2021 09:54:55 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [IPv6:2605:bc80:3010::138]) by lists.linuxfoundation.org (Postfix) with ESMTP id F11F7C002A for ; Tue, 8 Jun 2021 09:54:51 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id CD20482D61 for ; Tue, 8 Jun 2021 09:54:50 +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 xKaT2Gout9hJ for ; Tue, 8 Jun 2021 09:54:49 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from theia.8bytes.org (8bytes.org [IPv6:2a01:238:4383:600:38bc:a715:4b6d:a889]) by smtp1.osuosl.org (Postfix) with ESMTPS id BAD4D82DFB for ; Tue, 8 Jun 2021 09:54:48 +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 AE20C434; Tue, 8 Jun 2021 11:54:45 +0200 (CEST) From: Joerg Roedel To: x86@kernel.org Subject: [PATCH v3 3/7] x86/sev-es: Disable IRQs while GHCB is active Date: Tue, 8 Jun 2021 11:54:35 +0200 Message-Id: <20210608095439.12668-4-joro@8bytes.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210608095439.12668-1-joro@8bytes.org> References: <20210608095439.12668-1-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 is there). 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 | 39 +++++++++++++++++++++++++-------------- 1 file changed, 25 insertions(+), 14 deletions(-) diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 4fd997bbf059..2a922d1b03c8 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -192,14 +192,23 @@ 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) +static __always_inline struct ghcb *sev_es_get_ghcb(struct ghcb_state *state, + unsigned long *flags) { struct sev_es_runtime_data *data; struct ghcb *ghcb; + /* + * Nothing shall interrupt this code path while holding the per-cpu + * GHCB. The backup GHCB is only for NMIs interrupting this path. + */ + local_irq_save(*flags); + data = this_cpu_read(runtime_data); ghcb = &data->ghcb_page; + + if (unlikely(data->ghcb_active)) { /* GHCB is already in use - save its contents */ @@ -479,7 +488,8 @@ 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 __always_inline void sev_es_put_ghcb(struct ghcb_state *state, + unsigned long flags) { struct sev_es_runtime_data *data; struct ghcb *ghcb; @@ -500,14 +510,17 @@ static __always_inline void sev_es_put_ghcb(struct ghcb_state *state) vc_ghcb_invalidate(ghcb); data->ghcb_active = false; } + + local_irq_restore(flags); } void noinstr __sev_es_nmi_complete(void) { struct ghcb_state state; + unsigned long flags; struct ghcb *ghcb; - ghcb = sev_es_get_ghcb(&state); + ghcb = sev_es_get_ghcb(&state, &flags); vc_ghcb_invalidate(ghcb); ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_NMI_COMPLETE); @@ -517,7 +530,7 @@ void noinstr __sev_es_nmi_complete(void) sev_es_wr_ghcb_msr(__pa_nodebug(ghcb)); VMGEXIT(); - sev_es_put_ghcb(&state); + sev_es_put_ghcb(&state, flags); } static u64 get_jump_table_addr(void) @@ -527,9 +540,7 @@ static u64 get_jump_table_addr(void) struct ghcb *ghcb; u64 ret = 0; - local_irq_save(flags); - - ghcb = sev_es_get_ghcb(&state); + ghcb = sev_es_get_ghcb(&state, &flags); vc_ghcb_invalidate(ghcb); ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_JUMP_TABLE); @@ -543,9 +554,7 @@ 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); - - local_irq_restore(flags); + sev_es_put_ghcb(&state, flags); return ret; } @@ -666,9 +675,10 @@ static bool __init sev_es_setup_ghcb(void) static void sev_es_ap_hlt_loop(void) { struct ghcb_state state; + unsigned long flags; struct ghcb *ghcb; - ghcb = sev_es_get_ghcb(&state); + ghcb = sev_es_get_ghcb(&state, &flags); while (true) { vc_ghcb_invalidate(ghcb); @@ -685,7 +695,7 @@ static void sev_es_ap_hlt_loop(void) break; } - sev_es_put_ghcb(&state); + sev_es_put_ghcb(&state, flags); } /* @@ -1333,6 +1343,7 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication) struct ghcb_state state; struct es_em_ctxt ctxt; enum es_result result; + unsigned long flags; struct ghcb *ghcb; /* @@ -1353,7 +1364,7 @@ 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_es_get_ghcb(&state, &flags); vc_ghcb_invalidate(ghcb); result = vc_init_em_ctxt(&ctxt, regs, error_code); @@ -1361,7 +1372,7 @@ 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_es_put_ghcb(&state, flags); /* 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