From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DCB0447F3DC; Tue, 15 Sep 2026 11:02:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789470180; cv=none; b=a0u7yDewwVzm1yq735e27VFaQV0DH41883kl6d9G39c1lv5Ag4QfkUL/1SSt7Pd08f8DwfeViG5w4/PQbWKsPzAeEzRiyGBB6V0hz3SCSFN5swrRzNF5bq+yKLwXQVmMAFkUZ+j3ungjHodgA0hqKNilLcgKwdEU08ghnHeRkeA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789470180; c=relaxed/simple; bh=ihg7jXz8JSSKR1IUw9CybInLjQ7vIlhBHejjJVrcWwA=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=Ll9fL9bjVfmPC4XeBD3gf77BQ0SJBR0uYz6B2RS5lr8QP+gD7SAMIr6U/bWB6CVOQqHYJkQoE7Hn1+QgGecHAnxzr1cyEYw9KF/FH0ZKQbKnSUyrGFShT7KYRDqK7wYZythLpstmHo7XoZyoanq0Y4D+ES612IUfhbfDlQvHpus= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=O6y0JxsY; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="O6y0JxsY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 11B711F000FF; Tue, 15 Sep 2026 11:02:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789470176; bh=HdvUk8Q3ueSrhOfWqCZhgkyYE00QElNPTkeeBBLbXe0=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=O6y0JxsYEz1iIUZ3Eofq2WE6MBYxnhCfUBQ42MgdTXBF7nHE7NPtAu0HxZXG33fcR i3FdxvJ2DRCWUYlMVdI/WXZvBjVBRn20gsAIaAs4MpWQhzrzTNxeByalrVofFOOfWQ +CiUDuPoIP10o9zJcikd1hPObVHHdCSiIA6eGGhwN9a1kX2LMERAejhSvFSTUhTLIt qaj57i5Q2Nt9M6RKL4pX72P/4GIIjtnB3f6sIpyCYMdmi8qv3FGPN5xqCh69irbxbs ZAByN3x1xSeJ2pwYwfQtw0Kg3pvjNVhjDRKEbnEoZ+wlV1ING2iMXQuVoodSW58OUN vHc2zGMzuWk5Q== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1x6Qw9-000000094IN-3MOM; Tue, 15 Sep 2026 11:02:53 +0000 Date: Tue, 15 Sep 2026 12:02:53 +0100 Message-ID: <86y0d26ale.wl-maz@kernel.org> From: Marc Zyngier To: Fuad Tabba Cc: oupton@kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, mark.rutland@arm.com, steven.price@arm.com, vdonnefort@google.com, qperret@google.com Subject: Re: [PATCH v3 12/18] KVM: arm64: Prevent host PC adjustments for protected vCPUs In-Reply-To: References: <20260914113338.159227-1-fuad.tabba@linux.dev> <20260914113338.159227-13-fuad.tabba@linux.dev> <8633vc6jag.wl-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: fuad.tabba@linux.dev, oupton@kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, mark.rutland@arm.com, steven.price@arm.com, vdonnefort@google.com, qperret@google.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Mon, 14 Sep 2026 15:43:16 +0100, Fuad Tabba wrote: > > > > + hyp_vcpu = pkvm_get_loaded_hyp_vcpu(); > > > + if (!hyp_vcpu || hyp_vcpu->host_vcpu != vcpu) > > > > Under which circumstances do we get hyp_vcpu->host_vcpu != vcpu? > > When EL2 calls __kvm_adjust_pc() on the hyp vCPU itself: > __kvm_vcpu_run() at guest entry and inject_sync64() in nvhe/sys_regs.c > both pass &hyp_vcpu->vcpu. There the vCPU passed is the one to adjust, > so it's returned as is. If this is the sole case, why not check for '&hyp_cpu->vcpu == vcpu' instead of this odd inequality? Thanks, M. -- Without deviation from the norm, progress is not possible.