From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 085FE2116F4 for ; Sat, 7 Mar 2026 00:32:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772843556; cv=none; b=c/z7JSDrRQFtKz3TQHiZr0qP/svwz9IilcHktLgrtlwzXzXUq3Tm4JNxL79io5inxA5wnGVF/njldVZwy/ObB2Ba14mFcBbZn7gGizsW6ujwE3WUXOJUM2TQ+tpowfvcman6FtMUeaqNXiBG45m7DiiToRTttx1xeNAUv9ypwJ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772843556; c=relaxed/simple; bh=U0tv/IWl1t9pY6gIGnpa4aUs8wxrbsgAYa/FtkOyp9E=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=OLdbv8CoZegR9LJ7bdAkTmTbirUnbRQ8ENzzo2+q2k2xefvjzkEPTBqDkGuEzOTr0QOPMm0986RUU5PZEYxk5UUQD3n0LIbwUnBVaIFXKa4LETb3+PyMZN7lKEaboYLRTezXINpQHjJTznrins4RMAaWSlAShR6TSwfZUPYaOoM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ZuG/m4wN; arc=none smtp.client-ip=209.85.216.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ZuG/m4wN" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-3598518beceso6628829a91.2 for ; Fri, 06 Mar 2026 16:32:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772843554; x=1773448354; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=GBuJGZTSukXT+UwxFGKWJrgzhOxt0s7jxcSwbrVM1KQ=; b=ZuG/m4wNpiWbnAV/x62Hno3LzDC2bFGGhF8M1DFqaup/8TxDkXu0VIavxnSjYS0ZqP G539TEhsj96mQ1E+kHfldU/msKtIaP63RFYOfSREFUcTb51nFyXF9KyMhsGZKm4dbn8N +9CShsnF/dd2iWF0ptpYX4grP8z4xK89LtfeQNNXePHOcreYDAXykcwuja7EECz2dTUr jjeY73Qq3uK7N9qhRnd5S4vhPIF56/QPto5asO1PdcvJPbX8Xtr2GhRQfVr8QxSFiSWR gxwQEscnnn6rBu9LBSX+35Uc6SVImLi4twBb7RmFxWz8Ud3bYcxc/ggRXw5l1bBKWO7/ SBoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772843554; x=1773448354; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=GBuJGZTSukXT+UwxFGKWJrgzhOxt0s7jxcSwbrVM1KQ=; b=ICjWAR+cCFZ8umz4AgnU9vgDMPWk09KSn9BRlZrh32uh5le3pdRhkDIoa4BqezNlA3 ZGeLo2kHcSsYOi+fTT9BWyJXnGEFw9VWHx5OZzqqPtvcOcYSpYrtZBidnV4tb0R2sezU WR8HK982Z2P0Ai8/9idhtAPOSVKWXgOFaouEyeRroFz9X461VV+futf+AAn3LlxF0TTW KI14BtxcRsn2FYwyB/mOOJicy3EFGhJDU5h+quJo62VmNmBUjnQWl68ErwVFfLzBzUrm WedJjpjZTUQxFf+XsTS0sBLjvrIkK9rqpW7PH59DucKefSR1GObM9qVK9PQjUppFEgda sBgw== X-Forwarded-Encrypted: i=1; AJvYcCVLEQyEEr2wK3+OxH5qOanOyUdsSL9nrxLjOD4sOWWVI5mIpQQsL5APHLr7GfOOoXxeiVskWtoX0XKV0Tw=@vger.kernel.org X-Gm-Message-State: AOJu0YyoWhEHn2Rpt732X4hp7ceA8cvjkGVuBmxSRcSWuVwRA8QbAbCN 6W4yJOw/Y5GAKJN1kVgh/HMwFLMcBQH8fR7NMUOvuJZveFuJKOXntnG8MI0A8l98YR/6lYfOwa7 1ZLsQbw== X-Received: from pjtn10.prod.google.com ([2002:a17:90a:c68a:b0:358:e8ed:94e4]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:28d0:b0:33b:b078:d6d3 with SMTP id 98e67ed59e1d1-359be314eb6mr3520595a91.23.1772843554253; Fri, 06 Mar 2026 16:32:34 -0800 (PST) Date: Fri, 6 Mar 2026 16:32:32 -0800 In-Reply-To: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260306210900.1933788-1-yosry@kernel.org> <20260306210900.1933788-2-yosry@kernel.org> Message-ID: Subject: Re: [PATCH v2 1/6] KVM: SVM: Use maxphyaddr in emulator RAX check for VMRUN/VMLOAD/VMSAVE From: Sean Christopherson To: Yosry Ahmed Cc: Jim Mattson , Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Fri, Mar 06, 2026, Yosry Ahmed wrote: > > > Right, but I am trying to have the #GP check for VMLOAD/VMSAVE behave > > > consistently with vls=1, whether it's done by the hardware or the > > > emulator. > > > > Consistency should not be an issue, since VLS cannot be enabled when > > the MAXPHYADDRs differ. VLS doesn't work in that scenario. > > Why? It's only broken if VMLOAD/VMSAVE is executed with a GPA that > exceeds the guest's MAXPHYADDR, but not the host's, right? So only > broken if the guest is misbehaving. > > Taking a step back, I am not disagreeing that VLS should not be used > with different MAXPHYADDRs, I am just saying it might be. KVM straight up doesn't support that (see my other reply). > All that being said, I am fine with using cpuid_maxphyaddr(vcpu) > instead of kvm_host.maxphyaddr. Will wait for Sean's feedback to > figure out if a new version is needed. LOL, Jim and I are of one mind when it comes to guest.MAXPHYADDR.