From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (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 03FEE1EFFB7 for ; Mon, 27 Apr 2026 20:16:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777320968; cv=none; b=kkSQMayPk7mMq+WdZ3RPxuMP38nfcMgbFA7rDURjFYBdDm7Mq18+d98bSuzoW+KHS6kI82EoITNqrmBJBtM61/7om8aUQmdaJ2SlQZ7fpL6JUX+PjaK9X4uNF8Thnk9xDlWgQE8VLb3A9QBlXSmsIcub+9iJfEiPrEAJVjePLio= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777320968; c=relaxed/simple; bh=0pyaCVHXgsT6I9pt2BF1dAfN0ny7N4Nnpln8hTmlsTk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=fxF+CD2pw5JcFYfFbHKfJXrOUBWppOBlGdpF6gXn4IIdbG6pGBN1auZG5qq5CroSRti9+IyE9nZ95XoAYCrvSajvJ3SK6prdnxwmjnxxB8HvYE2wuQEkYbMqBhST9uQKiqABP2JIyKSnbDTRH5RTEfqpNmQ8WCG6E0UtYICUnCw= 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=ogXGxo4U; arc=none smtp.client-ip=209.85.215.202 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="ogXGxo4U" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-c79943d2fbfso3041825a12.1 for ; Mon, 27 Apr 2026 13:16:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1777320966; x=1777925766; 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=z81ysjwpMZ5uawBPqHBIiqxE6MH7tzbIS2UPVOpwQ60=; b=ogXGxo4UGhU9LnrnHjcVVfTQqsYj0/Xl3K6NkE5JNWNd/z7wE1FGNf8oQTqoi5kRHJ iFaD7Vd70i37b8Si/1vvYOiMzlyJprtEytheab1jF1hXAK95UokizWe1wWI1B7qk5h2A mlrphtI2GTi4ZGzrL/CcXLPTRIhu/QOY5yF+5D87jlO/S4jGxJerkG0y6lPN7ggCFtQo X3fkr0ROwmBvDz2QwNLDOS++LTJR9eMOYfRc8WkMupvTPcAG80kf9dysEFXPcO1f3jav sCZFNcAHwkrhwDFGDwf6QWxZRrCibi5U2vtsLhb6RhsBw4KqlgdH5WIxO9Cw39KXnEbK /mbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777320966; x=1777925766; 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=z81ysjwpMZ5uawBPqHBIiqxE6MH7tzbIS2UPVOpwQ60=; b=ZqNYT5up6OxUzxEgiOzpAlF65SqlrxSugYbZ1NF3a6JLz63V1pBzaN1EWKBeDs6TnQ PjHR5yBwDi1RTh15pRIcFPzzZ8WhbEeKsoFUUojurfjv15jmqm43IA/oHsgU2URtVVSV lcrJPrGxA0NBq7LySLF4m/j6nuV/5+CUL6bcEeXK3ItUsMIlQ6JwMA7f4goQeOBXEEu1 sqbDBy/HJxXYRv2c87x9riq9PxjtE0cvfoB9Qg13CEPHFxFptpZ93c8uVN7Xs6sVwPJX AJQfup8QW0FIj8z6oZHARALz0g8hOqKZwnOgATCVVF0hc0OzaJhWFBe6Lbdih/VnsG5t 4XQA== X-Forwarded-Encrypted: i=1; AFNElJ9ExQuy6wktLfX/N8udciJ/ZrcZNzJdpMYb4cR+inTO9k6BPFLCJYbEfbJfSBAeIvNp+W8=@vger.kernel.org X-Gm-Message-State: AOJu0YxYhKxZyFD8/n7UMoOBUs2+i9S8Tr+I4qRh52P0QZ69nQDNJq/6 zI2hBUAw8nrwUfaQ5haRO3kxUBL7TIBMhbDZfQ/P4IKAX6yW4b6XeAxg3dLkmDls66H3Tq3TYFk 5ovfJEA== X-Received: from pfaw4.prod.google.com ([2002:a05:6a00:ab84:b0:82c:e9cd:a73f]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:a121:b0:39f:acae:f12e with SMTP id adf61e73a8af0-3a39c10fdc2mr208396637.22.1777320965791; Mon, 27 Apr 2026 13:16:05 -0700 (PDT) Date: Mon, 27 Apr 2026 13:16:04 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260407063245.2755579-1-nikunj@amd.com> <20260407063245.2755579-8-nikunj@amd.com> <34cfe5e8-756a-435a-a73d-54bf69801161@amd.com> <3e4641288d7791919abf1a5b02b80431285484e5.camel@intel.com> <977e805339a29ab789650aa18cd320dd1e9e0c25.camel@intel.com> <6688fe2e-c723-404a-80e1-3f4c5f5cc4c6@amd.com> Message-ID: Subject: Re: [PATCH v6 7/7] KVM: SVM: Add Page modification logging support From: Sean Christopherson To: Tom Lendacky Cc: Kai Huang , "kvm@vger.kernel.org" , "pbonzini@redhat.com" , "joao.m.martins@oracle.com" , "nikunj@amd.com" , "bp@alien8.de" Content-Type: text/plain; charset="us-ascii" On Sat, Apr 25, 2026, Tom Lendacky wrote: > On 4/24/26 11:25, Tom Lendacky wrote: > >> Now, maybe the APM is trying to say only the save area is undefined, in which > >> case PML Index is fine and can and should be left alone. But if that's the case, > >> the APM needs to be updated to make explicitly clear what fields in the VMCS are > >> and are not valid after SHUTDOWN. > > > > I'm checking to see if I can get clarification on this. > > PML_INDEX will be valid even when a SHUTDOWN is intercepted. I'm working > to see if we can update the APM to identify what would be valid and what > wouldn't be in this situation. > > For a triple-fault SHUTDOWN, the saved x86 state could be inconsistent > because the CPU stopped in the middle of a sequence and redirected to > shutdown. Everything will be saved, but it might not be valid x86 state. Yeah, I assumed that the APM wording was an overly-broad description of why guest state would be garbage. > The question then becomes are there fields within the VMCB control area > that are based on x86 state that might not be valid (e.g. V_IRQ or nRIP, > etc.). FWIW, even a conservative iset of "these fields/areas are guaranteed to be sane and consistent" would be super helpful. The big problem right now is that the wording reads like the entire GHCB is suspect.