From nobody Sun Oct 5 21:42:49 2025 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 892C82C3278 for ; Tue, 29 Jul 2025 22:55:59 +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=1753829761; cv=none; b=UgNR5WJJcCdeuqVS+e0SnmWhHFWZUpSitQrR1PHOXfx3poTYezude6Sgm+RlP0cAV0DjEBnmrET9ZX0Z77R4ObR6+AX44BImmFZNz+tENme+XqnQV3g1GBq56rjrXHo3uSQTCQLGZs0jpxXvVL3mTpuFifvStFxk3O5xrI4az0c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753829761; c=relaxed/simple; bh=tSmg9vevb3jqaRkYY5Aaxyc4WM6Wx1gkdAMDVUweHc0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=HpRX4xdkma0hpgN5paJ470I80IpPbTMtMX2PrC92d6RKTi80c9GGw7UH+aF9X7yaQ+N8QI0DyXvB/YqLGfPaSYZwJDxwJTERXjmraRuwYtRx1c1aAP26r8fy6FqE47WnzwpPz472D3rzKHE7wwhYvzJUs1LQ92zYTgAyyIaXgRQ= 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=d9Ym5cDb; 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="d9Ym5cDb" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-31f030b1cb9so3516676a91.2 for ; Tue, 29 Jul 2025 15:55:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1753829759; x=1754434559; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=zsUJ7ZFybSscOwB+F/7yDFweXn/Ii9vNr67NR9vaee0=; b=d9Ym5cDbs7fWqK8y0va9sMhiJz9HWxKDpkD3oHqYVKUdzWSxLx0F21Do4mfQgy4JjG 6WMV0w6p08tsxqf0BdwO8l4Nz4rfTxIDJAX3Kvra0PgPeAJEasRzNtzJZq87yMXHCcIc iBtQ9pwrHmMbE99/4YFneaH8GAIBKJbUbt+q9hA/Pc9e5FkJLXMzOSXyxwDMk/D4RVxc tkVlsNlPrd/GMomRvcdlU8yUtHPgCerqI9Tnou3AOoTq5C4x+9jd4SE2X/gXbQzAMrZp r7rGUApfxTPyH2hc9ZVvi7XF3wJSQf15dY3+1HgJwaf6/y3IRcbR9NbrKs3Tu9ZXWobL 7OMg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1753829759; x=1754434559; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=zsUJ7ZFybSscOwB+F/7yDFweXn/Ii9vNr67NR9vaee0=; b=rH47yE8jAZWFoZ/PIWYt7b/mGLMi3sByYnWenYnVm4DMYoVV83IA9lUbyxBY+MM49+ 1VNy2MTBGTS1eZpNATL5IlwkZRA6Bop8xkXdvV3sUh9XsbruWB0QaZm6NH1JVJ/e4GoO 3r2l1Nw1Qg8qGq0AnDFVy9CgkNfnnaziXqypPq9S/qIscgpLcs0ckbN0kxXI7egvGCn7 mUMXQCIw+BFXI16fZWH5dMMSqgK8fiVWxD6Xu0yTXKMnccMEWcTLS5y/gUm1grJ5P12S 2oDGgaR1A4e3klPIP53V1W8FSGTxuZyGjdpP95X6qXLNlwjgl6xJi0JuwzydgUncD3rB y5/Q== X-Forwarded-Encrypted: i=1; AJvYcCX+8DYuQemaUOd1nZ05QTyehKsW21a5B2O9A3h437VCuES37LKws5Leo3SQ6aiRpL1cgrQbp7QVMo1uaUc=@vger.kernel.org X-Gm-Message-State: AOJu0YzfVcGxjHx9tYw8ZeT625EQTpApgBRjJWhw6lCOYPl7DQsLM59l 6xaQFcnj3bNVP9gdXqfpuwMPOj5kVbKK/uBLBd267PzXf04+X+4aPJqIX7kF42iIdG9fvLQZxjM hAMn+9A== X-Google-Smtp-Source: AGHT+IEUawy8XEGsXpdKDRLNNEWp47UfSJOlj3wwR4Kg29zUXO4HT9ko5KQTWasgzc65ODEqhN4o5kIR7eM= X-Received: from pjsk9.prod.google.com ([2002:a17:90a:62c9:b0:311:462d:cb60]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90a:d604:b0:31f:3029:8854 with SMTP id 98e67ed59e1d1-31f5de5561dmr1600493a91.27.1753829758931; Tue, 29 Jul 2025 15:55:58 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 29 Jul 2025 15:54:47 -0700 In-Reply-To: <20250729225455.670324-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250729225455.670324-1-seanjc@google.com> X-Mailer: git-send-email 2.50.1.552.g942d659e1b-goog Message-ID: <20250729225455.670324-17-seanjc@google.com> Subject: [PATCH v17 16/24] KVM: x86/mmu: Handle guest page faults for guest_memfd with shared memory From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Sean Christopherson Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, Ira Weiny , Gavin Shan , Shivank Garg , Vlastimil Babka , Xiaoyao Li , David Hildenbrand , Fuad Tabba , Ackerley Tng , Tao Chan , James Houghton Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Ackerley Tng Update the KVM MMU fault handler to service guest page faults for memory slots backed by guest_memfd with mmap support. For such slots, the MMU must always fault in pages directly from guest_memfd, bypassing the host's userspace_addr. This ensures that guest_memfd-backed memory is always handled through the guest_memfd specific faulting path, regardless of whether it's for private or non-private (shared) use cases. Additionally, rename kvm_mmu_faultin_pfn_private() to kvm_mmu_faultin_pfn_gmem(), as this function is now used to fault in pages from guest_memfd for both private and non-private memory, accommodating the new use cases. Co-developed-by: David Hildenbrand Signed-off-by: David Hildenbrand Signed-off-by: Ackerley Tng Co-developed-by: Fuad Tabba Signed-off-by: Fuad Tabba [sean: drop the helper] Signed-off-by: Sean Christopherson Reviewed-by: Xiaoyao Li --- arch/x86/kvm/mmu/mmu.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index e83d666f32ad..56c80588efa0 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4561,8 +4561,8 @@ static void kvm_mmu_finish_page_fault(struct kvm_vcpu= *vcpu, r =3D=3D RET_PF_RETRY, fault->map_writable); } =20 -static int kvm_mmu_faultin_pfn_private(struct kvm_vcpu *vcpu, - struct kvm_page_fault *fault) +static int kvm_mmu_faultin_pfn_gmem(struct kvm_vcpu *vcpu, + struct kvm_page_fault *fault) { int max_order, r; =20 @@ -4589,8 +4589,8 @@ static int __kvm_mmu_faultin_pfn(struct kvm_vcpu *vcp= u, { unsigned int foll =3D fault->write ? FOLL_WRITE : 0; =20 - if (fault->is_private) - return kvm_mmu_faultin_pfn_private(vcpu, fault); + if (fault->is_private || kvm_memslot_is_gmem_only(fault->slot)) + return kvm_mmu_faultin_pfn_gmem(vcpu, fault); =20 foll |=3D FOLL_NOWAIT; fault->pfn =3D __kvm_faultin_pfn(fault->slot, fault->gfn, foll, --=20 2.50.1.552.g942d659e1b-goog