From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-207.mta0.migadu.com (out-207.mta0.migadu.com [91.218.175.207]) (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 E93F62FE0F for ; Thu, 19 Oct 2023 19:06:06 +0000 (UTC) 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="oQgChljY" Date: Thu, 19 Oct 2023 19:05:58 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1697742363; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RLHQdgbSkkxaLwkcFuueBvH7VycJBav8fBuH03XXBKY=; b=oQgChljYtL/bUrXu6LUkQIGrJjc8WiMnPJS8uSqF2+0i85LF0qAbU6vRorb3R0acf+NEdw gZcIJiAeOfohEj96llKypUMIb4sxUnfqGRyEqX7ybGc8+qgLJHdDMTQZKuEBMCAeSa9VIN TrPbM/1wjV8d1yKxluF426hrzLWEA+M= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Raghavendra Rao Ananta Cc: Eric Auger , Marc Zyngier , Alexandru Elisei , James Morse , Suzuki K Poulose , Paolo Bonzini , Zenghui Yu , Shaoqin Huang , Jing Zhang , Reiji Watanabe , Colton Lewis , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Subject: Re: [PATCH v7 03/12] KVM: arm64: PMU: Clear PM{C,I}NTEN{SET,CLR} and PMOVS{SET,CLR} on vCPU reset Message-ID: References: <20231009230858.3444834-1-rananta@google.com> <20231009230858.3444834-4-rananta@google.com> <53546f35-f2cc-4c75-171c-26719550f7df@redhat.com> <34959db4-01e9-8c1e-110e-c52701e2fb19@redhat.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Migadu-Flow: FLOW_OUT Hi Raghu, Can you please make sure you include leading and trailing whitespace for your inline replies? The message gets extremely dense and is difficult to read. Also -- delete any unrelated context from your replies. If there's a localized conversation about a particular detail there's no reason to keep the entire thread in the body. On Thu, Oct 19, 2023 at 11:46:22AM -0700, Raghavendra Rao Ananta wrote: > On Wed, Oct 18, 2023 at 2:16 PM Raghavendra Rao Ananta > wrote: > > I had a brief discussion about this with Oliver, and it looks like we > > might need a couple of additional changes for these register accesses: > > - For the userspace accesses, we have to implement explicit get_user > > and set_user callbacks that to filter out the unimplemented counters > > using kvm_pmu_valid_counter_mask(). > Re-thinking the first case: Since these registers go through a reset > (reset_pmu_reg()) during initialization, where the valid counter mask > is applied, and since we are sanitizing the registers with the mask > before running the guest (below case), will implementing the > {get,set}_user() add any value, apart from just keeping userspace in > sync with every update of PMCR.N? KVM's sysreg emulation (as seen from userspace) fails to uphold the RES0 bits of these registers. That's a bug. -- Thanks, Oliver