From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 57B0C60A261F for ; Wed, 11 Nov 2026 08:28:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=PxX5TAPV; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=fUpnCIrZ 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: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:In-Reply-To:References: List-Unsubscribe-Post:List-Owner; bh=N91MbDTn6PrZLQH4j0EMDImQVrWd5RIhvpEq9PwZqyU=; b=PxX5TAPVDMyqzJYh4og1ydp6+U XyrftoNzDk/vbCdDx2uKfmtw/7A2tiW0TX0A6taaFhwHTYFBqF/O0QrkqqzsLdgqtNpCEP68qONaD KQH+p6+0hKHHJz6vjACC+0IiGEWw3tSCJRWF0cvcYFlAgAYq9IyLHb+nCAWqNIb/BAAVt+eih/k4F q1viO/Sa1s9WqslV/2T/LUj3KbWz7VarBA4i+BNbIrlPB1Sp1jtIvFWERpfF3+GqPzU9DU3rAXvHq uNZN3vXLMtkjSkKYY39gwxIorDXLMvnSzDgZOSAwYyYUtP/Hzyug03HpdWTZzZhAGMCVD9K0x6bqI wqCKpL9A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xR3gQ-000000062j3-1c1S; Wed, 11 Nov 2026 08:27:54 +0000 Received: from out-116.mta0.migadu.com ([2001:41d0:1004:224b::74] helo=mta0.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xR3gM-000000062ga-1Asv for linux-arm-kernel@lists.infradead.org; Wed, 11 Nov 2026 08:27:52 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=o5IReJ970IqTd3Q+Wne7cEMsCpUkcKmOzJbHBxuzgfo=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794385667; v=1; x=1794990467; b=fUpnCIrZd23Io7qMIYZ6W9iazjztqKF2N73IFzTIBAt40sA91DmxYkB16ZxQWGDpu0lLYp3f EQMemSIcrVbY3zJolfqBxv0N3/Baza7+YU0yucIBL22zL/YU7J1B2KBRnE5LbhNm101vNbi2dzW HVT0jXXk/HQ+gMuK6nmYNCSc= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id 8550fa73e993f6e8; Wed, 11 Nov 2026 08:27:46 +0000 X-Mizu-Trace-ID: 8550fa73e993f6e8 X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Marc Zyngier , Oliver Upton Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Mark Rutland , Vincent Donnefort , Fuad Tabba Subject: [PATCH] KVM: arm64: Sync SCTLR_EL1 before a pVM's CPU_ON reads its endianness Date: Wed, 11 Nov 2026 08:27:46 +0000 Message-ID: <20261111082746.1064567-1-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.47.3 X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261111_002750_469215_0E5EA88A X-CRM114-Status: UNSURE ( 8.41 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.1 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 pKVM handles a protected guest's PSCI CPU_ON at EL2 before the guest's EL1 sysregs are saved, so kvm_vcpu_is_be() reads a stale SCTLR_EL1. A guest that changes SCTLR_EL1.EE and calls CPU_ON before its next exit to the host starts the target vCPU with the old endianness. Sync SCTLR_EL1 before the read, as inject_sync64() does. Fixes: 9d4ec80be2eb4 ("KVM: arm64: Handle PSCI calls for protected VMs at EL2") Signed-off-by: Fuad Tabba --- Notes: inject_sync64() is the only other reader on a protected guest's exit path of a guest-writable EL1 sysreg's copy, and it syncs that register first. Saving SCTLR_EL1 before the in-loop exit handlers instead would put the save on every protected exit for two readers. A non-protected guest's CPU_ON is handled by the host, after the sysregs are saved. arch/arm64/kvm/hyp/nvhe/pkvm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index fc0475f0877d1..e421f45383e0d 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -1321,6 +1321,9 @@ static bool pvm_psci_vcpu_on(struct pkvm_hyp_vcpu *hyp_vcpu) goto error; } + /* Sync SCTLR_EL1 for kvm_vcpu_is_be(), as HVCs are handled before sysregs are resync'ed. */ + __vcpu_assign_sys_reg(&hyp_vcpu->vcpu, SCTLR_EL1, read_sysreg_el1(SYS_SCTLR)); + reset_state = &target->vcpu.arch.reset_state; WRITE_ONCE(reset_state->pc, smccc_get_arg2(&hyp_vcpu->vcpu)); WRITE_ONCE(reset_state->r0, smccc_get_arg3(&hyp_vcpu->vcpu)); base-commit: 7475ea8b58616b33c04afb976cf0fbaad9dd63fb -- 2.47.3