yeahuh / rpms / qemu-kvm

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From 6f572c45ff2c2376a16cd15882067d7fdcd74a83 Mon Sep 17 00:00:00 2001
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From: Alex Williamson <alex.williamson@redhat.com>
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Date: Tue, 5 Nov 2013 15:30:40 +0100
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Subject: [PATCH 12/25] vfio-pci: Add support for MSI affinity
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Alex Williamson <alex.williamson@redhat.com>
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Message-id: <20131105153040.15749.78283.stgit@bling.home>
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Patchwork-id: 55413
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O-Subject: [RHEL7 qemu-kvm PATCH v2 2/2] vfio-pci: Add support for MSI affinity
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Bugzilla: 1025477
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RH-Acked-by: Bandan Das <bsd@redhat.com>
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Jeffrey Cody <jcody@redhat.com>
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Bugzilla: 1025477
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Upstream commit: c7679d450ee021eb0826be65e4e018884443643a
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When MSI is accelerated through KVM the vectors are only programmed
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when the guest first enables MSI support.  Subsequent writes to the
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vector address or data fields are ignored.  Unfortunately that means
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we're ignore updates done to adjust SMP affinity of the vectors.
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MSI SMP affinity already works in non-KVM mode because the address
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and data fields are read from their backing store on each interrupt.
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This patch stores the MSIMessage programmed into KVM so that we can
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determine when changes are made and update the routes.
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Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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---
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 hw/misc/vfio.c |   47 ++++++++++++++++++++++++++++++++++++++++-------
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 1 file changed, 40 insertions(+), 7 deletions(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/misc/vfio.c |   47 ++++++++++++++++++++++++++++++++++++++++-------
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 1 files changed, 40 insertions(+), 7 deletions(-)
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diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
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index a072fd9..286dad1 100644
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--- a/hw/misc/vfio.c
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+++ b/hw/misc/vfio.c
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@@ -119,6 +119,7 @@ typedef struct VFIOINTx {
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 typedef struct VFIOMSIVector {
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     EventNotifier interrupt; /* eventfd triggered on interrupt */
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     struct VFIODevice *vdev; /* back pointer to device */
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+    MSIMessage msg; /* cache the MSI message so we know when it changes */
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     int virq; /* KVM irqchip route for QEMU bypass */
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     bool use;
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 } VFIOMSIVector;
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@@ -795,7 +796,6 @@ retry:
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     vdev->msi_vectors = g_malloc0(vdev->nr_vectors * sizeof(VFIOMSIVector));
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     for (i = 0; i < vdev->nr_vectors; i++) {
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-        MSIMessage msg;
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         VFIOMSIVector *vector = &vdev->msi_vectors[i];
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         vector->vdev = vdev;
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@@ -805,13 +805,13 @@ retry:
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             error_report("vfio: Error: event_notifier_init failed");
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         }
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-        msg = msi_get_message(&vdev->pdev, i);
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+        vector->msg = msi_get_message(&vdev->pdev, i);
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         /*
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          * Attempt to enable route through KVM irqchip,
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          * default to userspace handling if unavailable.
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          */
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-        vector->virq = kvm_irqchip_add_msi_route(kvm_state, msg);
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+        vector->virq = kvm_irqchip_add_msi_route(kvm_state, vector->msg);
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         if (vector->virq < 0 ||
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             kvm_irqchip_add_irqfd_notifier(kvm_state, &vector->interrupt,
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                                            vector->virq) < 0) {
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@@ -917,6 +917,33 @@ static void vfio_disable_msi(VFIODevice *vdev)
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             vdev->host.bus, vdev->host.slot, vdev->host.function);
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 }
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+static void vfio_update_msi(VFIODevice *vdev)
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+{
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+    int i;
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+
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+    for (i = 0; i < vdev->nr_vectors; i++) {
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+        VFIOMSIVector *vector = &vdev->msi_vectors[i];
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+        MSIMessage msg;
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+
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+        if (!vector->use || vector->virq < 0) {
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+            continue;
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+        }
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+
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+        msg = msi_get_message(&vdev->pdev, i);
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+
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+        if (msg.address != vector->msg.address ||
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+            msg.data != vector->msg.data) {
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+
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+            DPRINTF("%s(%04x:%02x:%02x.%x) MSI vector %d changed\n",
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+                    __func__, vdev->host.domain, vdev->host.bus,
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+                    vdev->host.slot, vdev->host.function, i);
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+
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+            kvm_irqchip_update_msi_route(kvm_state, vector->virq, msg);
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+            vector->msg = msg;
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+        }
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+    }
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+}
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+
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 /*
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  * IO Port/MMIO - Beware of the endians, VFIO is always little endian
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  */
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@@ -1834,10 +1861,16 @@ static void vfio_pci_write_config(PCIDevice *pdev, uint32_t addr,
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         is_enabled = msi_enabled(pdev);
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-        if (!was_enabled && is_enabled) {
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-            vfio_enable_msi(vdev);
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-        } else if (was_enabled && !is_enabled) {
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-            vfio_disable_msi(vdev);
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+        if (!was_enabled) {
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+            if (is_enabled) {
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+                vfio_enable_msi(vdev);
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+            }
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+        } else {
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+            if (!is_enabled) {
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+                vfio_disable_msi(vdev);
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+            } else {
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+                vfio_update_msi(vdev);
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+            }
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         }
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     } else if (pdev->cap_present & QEMU_PCI_CAP_MSIX &&
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         ranges_overlap(addr, len, pdev->msix_cap, MSIX_CAP_LENGTH)) {
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-- 
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1.7.1
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