From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-185.mta0.migadu.com (out-185.mta0.migadu.com [91.218.175.185]) (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 EE2E834DCEA for ; Fri, 5 Sep 2025 12:28:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.185 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757075304; cv=none; b=LaqiPO+SLM8EgM42HCiTO5AxAiNvIllVllUKTEENdNiUnNE86aNSD2rq7x45SXL9Y1bDyhmFOHIcK5PhhpabRxUl00JpkMk0fSdu0jv2o4O4Qb6QnNs4u2SCC9FDuJjRRk4Tnlf0vZa17S5OgJjoJ9YSLjc9r7sahbCOwy27ml8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757075304; c=relaxed/simple; bh=ibsTdOKVTHzOiHGtxFfaN4rsNCes07pwocidoYo27qU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HnB1rQnALX+eHkQWuitW2vdSBR0eiEIhy4b7mMDWuPP2hGd8eWN9xeuvVM98rSqEZdR2fHl0rND9rJ5hj6QNQBoqShZckGwLvWwwLo92rjSlemdHmlMcbRHr5hICZQHDNkOUdCnY8/nrPoUOQFS2qkOjuaYAhedvAegsgZw0jOs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=KNC6dl7f; arc=none smtp.client-ip=91.218.175.185 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="KNC6dl7f" Date: Fri, 5 Sep 2025 01:55:36 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1757075296; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=vtFqcEiQjlP0wLvGnyIFtDon3XMCTw+C5caJDyk77/Y=; b=KNC6dl7fy6EMOtqwVEw19yQPzfqr52NVN5XQjOmo9jd9KssNF3iH4BVXL+h8nMGxz7cGQR lWxav3WuCI5idW4Neu/3sRvXpn8lPKjkntlIV3G7Yugkry9orDdxFZnhEgC1YH3s403sai /iJa8R7S3uvAPbCzbdf4jEC5U6jociM= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Marc Zyngier Cc: kvmarm@lists.linux.dev, Joey Gouly , Suzuki K Poulose , Zenghui Yu Subject: Re: [PATCH 4/5] KVM: arm64: vgic-v3: Don't require IRQs be disabled for LPI xarray lock Message-ID: References: <20250904062348.223976-1-oliver.upton@linux.dev> <20250904062348.223976-5-oliver.upton@linux.dev> <87plc5z58m.wl-maz@kernel.org> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87plc5z58m.wl-maz@kernel.org> X-Migadu-Flow: FLOW_OUT On Fri, Sep 05, 2025 at 09:13:45AM +0100, Marc Zyngier wrote: > > diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c > > index 480391a0dcad..a21b482844ce 100644 > > --- a/arch/arm64/kvm/vgic/vgic.c > > +++ b/arch/arm64/kvm/vgic/vgic.c > > @@ -28,7 +28,7 @@ struct vgic_global kvm_vgic_global_state __ro_after_init = { > > * kvm->arch.config_lock (mutex) > > * its->cmd_lock (mutex) > > * its->its_lock (mutex) > > - * vgic_dist->lpi_xa.xa_lock must be taken with IRQs disabled > > + * vgic_dist->lpi_xa.xa_lock > > Doesn't this contradict the commit message statement that we always > take this lock with interrupts disabled? [ relaying offline conversation ] The changelog sucks hard on this one, what I was trying to say is there are no longer any writers that acquire the xa_lock with IRQs disabled. What remains is readers that have interrupts disabled, although readers are RCU-protected and don't take the lock. Thanks, Oliver