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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D870AC624D1 for ; Mon, 31 Aug 2026 16:35:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TGeLCE2hhCFr9nAJ5Io6groBvWf77qCVmB0f14eui14=; b=Y56XfHNyk/j8ApYTrwHuWJDrdu tvfY+dbLOPK+wYQFt0Aj4bWVwARoz6TlnoemfDKo207PCSfsZxzS/QAZqqzEddNUN/FnhQcVAKPBG zEI8KIOvcne2yyNZjE4Gs6Z3nxzgTSTO+KYSKlLjm1crrDv+ZBGDn/IvpY7Z1t+knsX0GoZ02z4Vn wUV2MlLSLqprAfAxtVpV+4RtwGMBkACj8p6RW1a9QOvVWlD1OEtOXvVTSWQ4Tq41OBCl5Ojl9x2CH OBSceDm6mfnHIdycI23IfSU5NFiBK0UcqZLq5okXyCZPOwEsyhBT853avlb54qtCkP1knl2Poz640 TTFgqQPg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x14yS-0000000A3y2-4BRI; Mon, 31 Aug 2026 16:35:09 +0000 Received: from out-228.mta1.migadu.com ([2001:41d0:203:375::e4] helo=mta1.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x14yL-0000000A3pN-01vq for linux-arm-kernel@lists.infradead.org; Mon, 31 Aug 2026 16:35:02 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=ec5kDs1hV1OOLEma4cNEIwqbZPM8R9T+UNCDcFGQGN0=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1788194099; v=1; x=1788798899; b=nadAHiPomKsQjHI84HxMKyGStAHECus/8Z6w0V/l1GcUoFLJLQqagQ9q91PLuhUsTtCl0sNJ deUUWMt3d8mE2JYURZ7G3jnQT+AV2kvNoO77oP1vm8ibjNvSviIgCTighlw0Mzxd9+jq5dPY94a M7o7+BpiaT/kZZlePM7VNheI= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id b40c3e22dec0421f; Mon, 31 Aug 2026 16:34:58 +0000 X-Mizu-Trace-ID: b40c3e22dec0421f X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Marc Zyngier , Oliver Upton , kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Catalin Marinas , Will Deacon , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Vincent Donnefort , Quentin Perret , Fuad Tabba Subject: [PATCH 12/17] KVM: arm64: Inject an UNDEF at EL2 for unhandled protected guest exits Date: Mon, 31 Aug 2026 17:34:16 +0100 Message-Id: <20260831163421.272420-13-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260831163421.272420-1-fuad.tabba@linux.dev> References: <20260831163421.272420-1-fuad.tabba@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260831_093501_222154_0FF4BA34 X-CRM114-Status: GOOD ( 13.03 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Make pvm_exit_handlers[] an allow-list: a protected guest's exit class is handled at EL2, forwarded where the host emulates it, or results in an UNDEF at EL2. Any other class, once forwarded, would re-execute forever. The host resolves such an exit by injecting an exception or incrementing the PC. The marshalling that follows allows neither: a protected vCPU takes only the UNDEF on a SYS64 trap and the external abort on a forwarded IABT or DABT that EL2 builds for it. WFxT takes the UNDEF, as it is not offered to protected guests. FP/SIMD keeps the lazy switch, and the watchpoint entry is dropped: a protected vCPU runs with TDE clear. Signed-off-by: Fuad Tabba --- arch/arm64/kvm/hyp/nvhe/switch.c | 29 +++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c index 7318e3e6a5f36..afddcf14f366e 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -203,15 +203,36 @@ static const exit_handler_fn hyp_exit_handlers[] = { [ESR_ELx_EC_MOPS] = kvm_hyp_handle_mops, }; +/* WFI/WFE exit to the host, which emulates them. WFxT is not offered. */ +static bool kvm_handle_pvm_wfx(struct kvm_vcpu *vcpu, u64 *exit_code) +{ + if (kvm_vcpu_get_esr(vcpu) & ESR_ELx_WFx_ISS_WFxT) + return kvm_handle_pvm_restricted(vcpu, exit_code); + + return false; +} + +/* Lazy FP/SIMD switch, or the UNDEF the host would otherwise be asked for. */ +static bool kvm_handle_pvm_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code) +{ + if (kvm_hyp_handle_fpsimd(vcpu, exit_code)) + return true; + + return kvm_handle_pvm_restricted(vcpu, exit_code); +} + +/* + * A class not listed takes an UNDEF at EL2: the host has no way to + * inject one into a protected vCPU. + */ static const exit_handler_fn pvm_exit_handlers[] = { - [0 ... ESR_ELx_EC_MAX] = NULL, + [0 ... ESR_ELx_EC_MAX] = kvm_handle_pvm_restricted, + [ESR_ELx_EC_WFx] = kvm_handle_pvm_wfx, [ESR_ELx_EC_HVC64] = kvm_handle_pvm_hvc64, [ESR_ELx_EC_SYS64] = kvm_handle_pvm_sys64, - [ESR_ELx_EC_SVE] = kvm_handle_pvm_restricted, - [ESR_ELx_EC_FP_ASIMD] = kvm_hyp_handle_fpsimd, + [ESR_ELx_EC_FP_ASIMD] = kvm_handle_pvm_fpsimd, [ESR_ELx_EC_IABT_LOW] = kvm_hyp_handle_iabt_low, [ESR_ELx_EC_DABT_LOW] = kvm_hyp_handle_dabt_low, - [ESR_ELx_EC_WATCHPT_LOW] = kvm_hyp_handle_watchpt_low, [ESR_ELx_EC_MOPS] = kvm_hyp_handle_mops, }; -- 2.39.5