From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 CB623433A5; Thu, 17 Apr 2025 18:45:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744915555; cv=none; b=LO1ztORvz++HvTKgszU0KgDoClavkHCpxG+/AH8nasUd5HyP3WGgbRb2knkk1Do75luHtDFareCSZf+KEM+1VQ0/Cbeq+JwdA/EMeK/1mdT8MhOigN/dLAym8RKpyqvK1A4kV1ctMvOT/W+rEgCz3zmJ/oPl/5H4/XyWk6O/om0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744915555; c=relaxed/simple; bh=rPQUb4tktoGOFaJ/D4/uLGicL7f0jZB0ERG/f+weYr4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Xn4C2U8Yo4MrfGsGVNa/h2K/j7OXKrqBhVUZ1HKaMUHYdlSE743ZR7xrJHE6IW37uNY9WicW4t8LwwuNFop76/Lu1cVX+aPuqfqVf4kiZnskrljAl4GKi3KBMjlUPAPAJ6JtikI8f07I8ZcZNEp+OCQI88Rg47CiWEkmDa3iYCQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=wH97ZuXe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="wH97ZuXe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5ED90C4CEEA; Thu, 17 Apr 2025 18:45:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744915555; bh=rPQUb4tktoGOFaJ/D4/uLGicL7f0jZB0ERG/f+weYr4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wH97ZuXeCtTpRk3YPxHYNZpgIiu3VPd+FwZzNJVqq3NF3kl0VAwoor9+gfiPukU0A WJQjTcthDS5ZufQ+Zr6oDpRgHvUPupj8D8ZxqDiUGRqUREi3Jn+Ki/PdR7TTlyAACR yXteqg0M5TKP7G/yNxD7xXUuzUgnOU3IkN1b1mb4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Niklas Schnelle , Bjorn Helgaas , Matthew Rosato , Sasha Levin Subject: [PATCH 6.12 165/393] s390/pci: Fix s390_mmio_read/write syscall page fault handling Date: Thu, 17 Apr 2025 19:49:34 +0200 Message-ID: <20250417175114.224779329@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250417175107.546547190@linuxfoundation.org> References: <20250417175107.546547190@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Niklas Schnelle [ Upstream commit 41a0926e82f4963046876ed9a1b5f681be8087a8 ] The s390 MMIO syscalls when using the classic PCI instructions do not cause a page fault when follow_pfnmap_start() fails due to the page not being present. Besides being a general deficiency this breaks vfio-pci's mmap() handling once VFIO_PCI_MMAP gets enabled as this lazily maps on first access. Fix this by following a failed follow_pfnmap_start() with fixup_user_page() and retrying the follow_pfnmap_start(). Also fix a VM_READ vs VM_WRITE mixup in the read syscall. Link: https://lore.kernel.org/r/20250226-vfio_pci_mmap-v7-1-c5c0f1d26efd@linux.ibm.com Signed-off-by: Niklas Schnelle Signed-off-by: Bjorn Helgaas Reviewed-by: Matthew Rosato Signed-off-by: Sasha Levin --- arch/s390/pci/pci_mmio.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c index de5c0b389a3ec..4779c3cb6cfab 100644 --- a/arch/s390/pci/pci_mmio.c +++ b/arch/s390/pci/pci_mmio.c @@ -171,8 +171,12 @@ SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr, args.address = mmio_addr; args.vma = vma; ret = follow_pfnmap_start(&args); - if (ret) - goto out_unlock_mmap; + if (ret) { + fixup_user_fault(current->mm, mmio_addr, FAULT_FLAG_WRITE, NULL); + ret = follow_pfnmap_start(&args); + if (ret) + goto out_unlock_mmap; + } io_addr = (void __iomem *)((args.pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK)); @@ -305,14 +309,18 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr, if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) goto out_unlock_mmap; ret = -EACCES; - if (!(vma->vm_flags & VM_WRITE)) + if (!(vma->vm_flags & VM_READ)) goto out_unlock_mmap; args.vma = vma; args.address = mmio_addr; ret = follow_pfnmap_start(&args); - if (ret) - goto out_unlock_mmap; + if (ret) { + fixup_user_fault(current->mm, mmio_addr, 0, NULL); + ret = follow_pfnmap_start(&args); + if (ret) + goto out_unlock_mmap; + } io_addr = (void __iomem *)((args.pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK)); -- 2.39.5