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 6A4E0CA5FF1 for ; Wed, 7 Oct 2026 07:44:13 +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=BOt8WXidMcA/3vdws/pbowopZJuQh2QH9PqXo0bIoD8=; b=YxF6ewhyFOQtMfUpJYVfNo5llB 4NBGZbtERfvMnlbRil66/SnftZYaPbtMYHQaNeLEr5tmwQw2MPnFhJLldujLbVNIdaUThzOyLC7GH /PopbCYpByqDaSVGZrRS7QDrJZWe2MdA8GOxLrSrIEWr6J6vS/vt8NTWnskgkvv7eng53StdqLD7K uNSlxSBlEaNxypzdmhQrOtGmzEtKjZnk+dnyY9HAMFfomQli/uzZt2CzRr/6tXpWEyXSCHnvmT75z 13qpexiJKOQLX59xqQjp0C0OA4sdBNkY8erDDsod3qD0anNS4ALz/qnAuAb+qPyz9eiHK08STEdLf UqNs060A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xEMJo-00000001sp9-1zQW; Wed, 07 Oct 2026 07:44:04 +0000 Received: from out-234.mta0.migadu.com ([2001:41d0:1004:224b::ea] helo=mta0.migadu.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xEMJj-00000001slO-08vk for linux-arm-kernel@lists.infradead.org; Wed, 07 Oct 2026 07:44:03 +0000 X-Envelope-To: linux-arm-kernel@lists.infradead.org DKIM-Signature: a=rsa-sha256; bh=DEbyYnw/QNFLD6hov3Wk8Emu00bFpjJHBWq6l30twn8=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791359037; v=1; x=1791963837; b=aGPFpe5P2U1a2h5r0OF0MkW5Gu+NyzjGqTEcYXVPnD1iJnlN3MPpEqMtzbiQcDoYtcgpbD+Q Nn1lPFaUInJdTJD1pih9WHXMLkwTLZMvtFdPX8YZ0+lPC3Q/bFRN8SQlNx/tG7yUDuvwL3DSz8Q 6zmEtAaCc3kvI4de2msa+ZpM= X-Envelope-To: linux-arm-kernel@lists.infradead.org Received: by smtp.migadu.com with ESMTPS id e4f7af71e98e56d0; Wed, 07 Oct 2026 07:43:56 +0000 X-Mizu-Trace-ID: e4f7af71e98e56d0 X-Migadu-Flow: FLOW_OUT From: Fuad Tabba To: Marc Zyngier , Oliver Upton Cc: Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , Zenghui Yu , Ganapatrao Kulkarni , Will Deacon , Fuad Tabba , kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH v2 2/3] KVM: arm64: nv: Read a guest hypervisor's CNTV_CVAL_EL0 from memory on x1e Date: Wed, 7 Oct 2026 08:43:42 +0100 Message-Id: <20261007074343.324269-3-fuad.tabba@linux.dev> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20261007074343.324269-1-fuad.tabba@linux.dev> References: <20261007074343.324269-1-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-20261007_004359_329281_1A350CE0 X-CRM114-Status: GOOD ( 11.90 ) 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 On x1e KVM keeps CNTVOFF_EL2 at zero, traps the virtual timer whenever it has an offset and programs the hardware with the offset applied. kvm_hyp_handle_timer() returns that hardware value for a VHE guest hypervisor's read of its own CNTV_CVAL_EL0, instead of the CVAL it wrote. Its writes trap to the kernel and land in CNTHV_CVAL_EL2, so return that, as the physical timer's read does without CNTPOFF_EL2. Fixes: 0bc9a9e85fcf ("KVM: arm64: Work around x1e's CNTVOFF_EL2 bogosity") Signed-off-by: Fuad Tabba --- arch/arm64/kvm/hyp/vhe/switch.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 14aada311bac4..4c965f9b1e1de 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -322,10 +322,14 @@ static bool kvm_hyp_handle_timer(struct kvm_vcpu *vcpu, u64 *exit_code) val = __vcpu_sys_reg(vcpu, CNTV_CVAL_EL0); break; case SYS_CNTV_CVAL_EL0: - if (vcpu_el2_e2h_is_set(vcpu)) - val = read_sysreg_el0(SYS_CNTV_CVAL); - else + if (vcpu_el2_e2h_is_set(vcpu)) { + if (has_broken_cntvoff() && timer_get_offset(vcpu_hvtimer(vcpu))) + val = __vcpu_sys_reg(vcpu, CNTHV_CVAL_EL2); + else + val = read_sysreg_el0(SYS_CNTV_CVAL); + } else { val = __vcpu_sys_reg(vcpu, CNTV_CVAL_EL0); + } break; case SYS_CNTVCT_EL0: case SYS_CNTVCTSS_EL0: -- 2.39.5