From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (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 5053E33263F for ; Wed, 10 Jun 2026 15:19:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781104743; cv=none; b=G+EQTg1/63+gdsdqnMV97le7zndUHIeEG21lHLbZc2EdLlWzkUwunWwot9wnH8KsDGkx7ntuKayP9V6mxbYDgWaLs50fKvx7l8KW60pC1xRI2RZN+PlLISj2BHyNy96YoBPhllsnt+THJVMuyez5Gf1fFit4O5AzN0ZBz19yZ34= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781104743; c=relaxed/simple; bh=UkLj+tZqpkffpEV5QRjxZQz63KWtzsiYYBPOPyc3h+Y=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=OyBW1EcgwGQwN5mpdd3UekylwgNPGKME0wIr3+2S4FQxvCyG0iL4/Yo/AwHyX+hRgGXPWrWGXNI9i5LX4k+wO5YSuqds3JQO9Z96oRHpS9uHAe4EpyPTbE4G64R0cUt/YBf9KVB6V4aOiqG7b+z1b/ETw6V968dBPcFtRpSmHfU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--praan.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=MKP784vD; arc=none smtp.client-ip=209.85.210.202 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--praan.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="MKP784vD" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-8422b544a4bso4362748b3a.3 for ; Wed, 10 Jun 2026 08:19:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1781104740; x=1781709540; 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=U0es0rdpo5zHpTGer7c4Y4kWiVEeVry4q+hd8CbVLqA=; b=MKP784vDc7UNawXDtsg5E7d6oNffWCVBigWrW1Ew20YpxmMB8ThtgADhHLGt7L6kRR q0D+IHtzvCZ3LcvOTJ45TLSAt2/WNKybrhMQi5DGQtZxdkX4XgsnRAqfsZB7sB0ooXzX 2WdWGa91rOez5S2tWKMbzMlXxJk//O1fW6tdEachK5wLhwUXxCShQ/iTgvJ4DGL+98pY Q32APzBQCU6zsbo2GVU7LZ/1ei0kouhczuWuIQr1CJEB3LyQ0Y4lGifnWrExvNhz1xvt IhugI5NV///6FTrnYxWBrnxSLKySqEX9Gq9fR5GaS69WOn42rXaNHGcVELgrcfraQqLr v2iQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781104740; x=1781709540; 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=U0es0rdpo5zHpTGer7c4Y4kWiVEeVry4q+hd8CbVLqA=; b=Ytl0DyDq4Fa7wa+AoT+lGc+1fz8Lfrso92tHJkXr0ykJBGpl/C3azh1TR7YYCuTsSJ LEuvDLh6CNaThTUUDljf+VeftzSefWp2GoTjrHg7sPadWEgezWyhIdjCHxUKmCYQybiu 56vm5XLFxauWEb+nNPx+Cbmv8KD2KHIMPd6BbuUk8ivmPE19Ni4eING6iiIoo5RfA6+5 Wuce+O3G9Asq/dnvWF8gZI/uS4iMAWvZx3+OoNVyCZAGi0PoogomJnk2twieHRGn2Fqx sQ5pBw2mepXxlQkR7ez3fnX0+XYkkK6JnTJOId8Tf9eJdg1tyYxing4NuCx8DrzupjBO sYUg== X-Forwarded-Encrypted: i=1; AFNElJ9DpLLRUYtYZVRHWs2g9fLdpkhegnRTdS6L4RJPlasonZ5twzlQ1ok9JMuoUgqZR77vigmOH1uOC+XW1I4=@vger.kernel.org X-Gm-Message-State: AOJu0YxH0BKKlIcl8anXpXsftbPwo0T3DIACinyWyG5cymdRmbjEyXCL NXiosKGsPPKChTEdUtCtx9TR0ydDAtphp9IVfstdecd2nvyr0lTjNVOd+NA7Lw4IZP3XqtrkN88 +7A== X-Received: from pfne8.prod.google.com ([2002:aa7:8248:0:b0:842:4f22:f388]) (user=praan job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:440a:b0:842:614e:cc9d with SMTP id d2e1a72fcca58-8430a70be01mr8519996b3a.27.1781104740313; Wed, 10 Jun 2026 08:19:00 -0700 (PDT) Date: Wed, 10 Jun 2026 15:18:50 +0000 In-Reply-To: <20260610151853.3608948-1-praan@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260610151853.3608948-1-praan@google.com> X-Mailer: git-send-email 2.54.0.1099.g489fc7bff1-goog Message-ID: <20260610151853.3608948-3-praan@google.com> Subject: [RFC PATCH 2/5] vfio/pci: Implement ZONE_DEVICE-backed P2P registration From: Pranjal Shrivastava To: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Bjorn Helgaas , Logan Gunthorpe , Alex Williamson , Jason Gunthorpe , Kevin Tian , Pranjal Shrivastava , Ankit Agrawal , Matt Evans , Vivek Kasireddy , Leon Romanovsky , Shivaji Kant , Samiullah Khawaja Content-Type: text/plain; charset="UTF-8" Implement the VFIO_DEVICE_FEATURE_P2P_REGISTER. A bitmask is added to track the registered regions. Post-registration, the BAR is added to the device's P2P pool and is available to be used with standard page-based APIs. Signed-off-by: Pranjal Shrivastava --- drivers/vfio/pci/vfio_pci_core.c | 39 ++++++++++++++++++++++++++++++++ include/linux/vfio_pci_core.h | 1 + 2 files changed, 40 insertions(+) diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index a28f1e99362c..1e922e3aaeb3 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -1554,6 +1554,43 @@ static int vfio_pci_core_feature_token(struct vfio_pci_core_device *vdev, return 0; } +static int vfio_pci_core_feature_p2p_register(struct vfio_pci_core_device *vdev, + u32 flags, u32 __user *arg, + size_t argsz) +{ + u32 bar_index; + int ret; + + ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET, + sizeof(bar_index)); + if (ret != 1) + return ret; + + if (copy_from_user(&bar_index, arg, sizeof(bar_index))) + return -EFAULT; + + if (bar_index >= PCI_STD_NUM_BARS) + return -EINVAL; + + if (!(pci_resource_flags(vdev->pdev, bar_index) & IORESOURCE_MEM)) + return -EINVAL; + + /* Already registered */ + if (vdev->p2p_registered_bars & (1 << bar_index)) + return 0; + + ret = pci_p2pdma_add_resource(vdev->pdev, bar_index, 0, 0); + if (ret && ret != -EEXIST) + return ret; + + vdev->p2p_registered_bars |= (1 << bar_index); + + pci_info(vdev->pdev, "BAR %d registered for ZONE_DEVICE P2P\n", + bar_index); + + return 0; +} + int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags, void __user *arg, size_t argsz) { @@ -1572,6 +1609,8 @@ int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags, return vfio_pci_core_feature_token(vdev, flags, arg, argsz); case VFIO_DEVICE_FEATURE_DMA_BUF: return vfio_pci_core_feature_dma_buf(vdev, flags, arg, argsz); + case VFIO_DEVICE_FEATURE_P2P_REGISTER: + return vfio_pci_core_feature_p2p_register(vdev, flags, arg, argsz); default: return -ENOTTY; } diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h index 5fc6ce4dd786..cae7f069e5b6 100644 --- a/include/linux/vfio_pci_core.h +++ b/include/linux/vfio_pci_core.h @@ -112,6 +112,7 @@ struct vfio_pci_core_device { struct vfio_pci_region *region; u8 msi_qmax; u8 msix_bar; + u8 p2p_registered_bars; u16 msix_size; u32 msix_offset; u32 rbar[7]; -- 2.54.0.1099.g489fc7bff1-goog