From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (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 B623663A; Tue, 12 Mar 2024 00:49:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710204546; cv=none; b=Z27mzcof5WElEaewsn4FGrnAoqoxWPP35WK5r/OmSV4qwKQyhTaJqbx6wbUHk6mskUL/PMl3AJ+duiICqRX/3Us8N8Psvuv5XPd1jaZWreJLZO+ipCesdV4+UU9WWOT0neeXE2RkyynrVOEo8fG8zwNjt+4M/V3pRRMd0s0QbyE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710204546; c=relaxed/simple; bh=9TL859kAz6MNTwXWb2gchLa6ho+GqIpgMKGxXDR4m0g=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=RpwcMK1/0OR15aObnGPyfkUrvANPtOXs/1aE0TlPwGYiLEDkJSSX+pizzk/OeBOh48IBksqWk6c3VmdR0iFS1UOYrBi+TYtjMt2mUKFEt4frDd3TJqgrcaR7iT8R8BT8+OhkelfCGq5k2XiyIyrTSx2ZjK/xv3Pdik4Y6SENgLw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=ACcM5M9b; arc=none smtp.client-ip=192.198.163.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="ACcM5M9b" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1710204545; x=1741740545; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=9TL859kAz6MNTwXWb2gchLa6ho+GqIpgMKGxXDR4m0g=; b=ACcM5M9bDmj5totl969sIKxJVIHzmTw/iYMt2YAFcaSsMEqOsxy+fncU QfaWF3+3dWIGw0AJrz68zVa/NyOmJVzby71n8GhGd0+YLmy1D22jtbnyD wyWbnbUgfvcYo7BrUJEpz8ODts5G4t1HlkeKeJvOp35OsPymkM3+tazxe 5hl0TPgp/ozaEJG8vPf3n1kk1PsZ9ATU0Z/HIMmLTSLAXU2QO8Ltcy0fu 0KBvUL5K+P83CQ5+necbuiMikUZfVdDmQrsAj4ZeBjKOEefmLkO865HKm T/BckppnLpzXxQnNNPwIP02uphRkMRLsXr5fHM8vQzybvT9HbyMB0T+Wj Q==; X-IronPort-AV: E=McAfee;i="6600,9927,11010"; a="8656546" X-IronPort-AV: E=Sophos;i="6.07,118,1708416000"; d="scan'208";a="8656546" Received: from fmviesa010.fm.intel.com ([10.60.135.150]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Mar 2024 17:49:03 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.07,118,1708416000"; d="scan'208";a="11259989" Received: from binbinwu-mobl.ccr.corp.intel.com (HELO [10.125.242.247]) ([10.125.242.247]) by fmviesa010-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Mar 2024 17:49:02 -0700 Message-ID: <35bc4582-8a03-413b-be0e-4cc419715772@linux.intel.com> Date: Tue, 12 Mar 2024 08:48:59 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 21/21] KVM: x86: Add gmem hook for determining max NPT mapping level To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, seanjc@google.com, michael.roth@amd.com, isaku.yamahata@intel.com, thomas.lendacky@amd.com References: <20240227232100.478238-1-pbonzini@redhat.com> <20240227232100.478238-22-pbonzini@redhat.com> From: Binbin Wu In-Reply-To: <20240227232100.478238-22-pbonzini@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2/28/2024 7:21 AM, Paolo Bonzini wrote: > From: Michael Roth > > In the case of SEV-SNP, whether or not a 2MB page can be mapped via a > 2MB mapping in the guest's nested page table depends on whether or not > any subpages within the range have already been initialized as private > in the RMP table. The existing mixed-attribute tracking in KVM is > insufficient here, for instance: > > - gmem allocates 2MB page > - guest issues PVALIDATE on 2MB page > - guest later converts a subpage to shared > - SNP host code issues PSMASH to split 2MB RMP mapping to 4K > - KVM MMU splits NPT mapping to 4K > > At this point there are no mixed attributes, and KVM would normally > allow for 2MB NPT mappings again, but this is actually not allowed > because the RMP table mappings are 4K and cannot be promoted on the > hypervisor side, so the NPT mappings must still be limited to 4K to > match this. > > Add a hook to determine the max NPT mapping size in situations like > this. > > Signed-off-by: Michael Roth > Message-Id: <20231230172351.574091-31-michael.roth@amd.com> > Signed-off-by: Paolo Bonzini > --- > arch/x86/include/asm/kvm-x86-ops.h | 1 + > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/mmu/mmu.c | 7 +++++++ > 3 files changed, 9 insertions(+) > > diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h > index 42474acb7375..436e3c157fae 100644 > --- a/arch/x86/include/asm/kvm-x86-ops.h > +++ b/arch/x86/include/asm/kvm-x86-ops.h > @@ -140,6 +140,7 @@ KVM_X86_OP(vcpu_deliver_sipi_vector) > KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons); > KVM_X86_OP_OPTIONAL(get_untagged_addr) > KVM_X86_OP_OPTIONAL_RET0(gmem_prepare) > +KVM_X86_OP_OPTIONAL_RET0(gmem_validate_fault) > KVM_X86_OP_OPTIONAL(gmem_invalidate) > > #undef KVM_X86_OP > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index e523b204697d..259e6bb1e447 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -1806,6 +1806,7 @@ struct kvm_x86_ops { > gva_t (*get_untagged_addr)(struct kvm_vcpu *vcpu, gva_t gva, unsigned int flags); > int (*gmem_prepare)(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, int max_order); > void (*gmem_invalidate)(kvm_pfn_t start, kvm_pfn_t end); > + int (*gmem_validate_fault)(struct kvm *kvm, kvm_pfn_t pfn, gfn_t gfn, u8 *max_level); Since it's named "gmem_validate_fault", can we just passed in the "fault" as an argument to avoid passing in pfn, gfn, max_level individually? I noticed in Isaku's TDX patch set, fault->private would also need to be passed in. > }; > > struct kvm_x86_nested_ops { > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 6b4cb71668df..bcf12ac489f9 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -4339,6 +4339,13 @@ static int kvm_faultin_pfn_private(struct kvm_vcpu *vcpu, > fault->max_level); > fault->map_writable = !(fault->slot->flags & KVM_MEM_READONLY); > > + r = static_call(kvm_x86_gmem_validate_fault)(vcpu->kvm, fault->pfn, > + fault->gfn, &fault->max_level); > + if (r) { > + kvm_release_pfn_clean(fault->pfn); > + return r; > + } > + > return RET_PF_CONTINUE; > } >