From: Roger Pau Monné <roger.pau@citrix.com>
Date: Mon, 2 Jul 2018 11:07:55 +0000 (+0200)
Subject: vpci/msi: fix update of bound MSI interrupts
X-Git-Tag: archive/raspbian/4.14.0+80-gd101b417b7-1+rpi1^2~63^2~3715
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=1e34ed7174cce6ab37e420dda9452267301fb7d2;p=xen.git

vpci/msi: fix update of bound MSI interrupts

Current update process of already bound MSI interrupts is wrong
because unmap_domain_pirq calls pci_disable_msi, which disables MSI
interrupts on the device. On the other hand map_domain_pirq doesn't
enable MSI, so the current update process of already enabled MSI
entries is wrong because MSI control bit will be disabled by
unmap_domain_pirq and not re-enabled by map_domain_pirq.

In order to fix this avoid unmapping the PIRQs and just update the
binding of the PIRQ. A new arch helper to do that is introduced.

Note that MSI-X is not affected because unmap_domain_pirq only
disables the MSI enable control bit for the MSI case, for MSI-X the
bit is left untouched by unmap_domain_pirq.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
---

diff --git a/xen/arch/x86/hvm/vmsi.c b/xen/arch/x86/hvm/vmsi.c
index acadc23f8d..3001d5c488 100644
--- a/xen/arch/x86/hvm/vmsi.c
+++ b/xen/arch/x86/hvm/vmsi.c
@@ -699,6 +699,29 @@ static int vpci_msi_update(const struct pci_dev *pdev, uint32_t data,
     return 0;
 }
 
+int vpci_msi_arch_update(struct vpci_msi *msi, const struct pci_dev *pdev)
+{
+    int rc;
+
+    ASSERT(msi->arch.pirq != INVALID_PIRQ);
+
+    pcidevs_lock();
+    rc = vpci_msi_update(pdev, msi->data, msi->address, msi->vectors,
+                         msi->arch.pirq, msi->mask);
+    if ( rc )
+    {
+        spin_lock(&pdev->domain->event_lock);
+        unmap_domain_pirq(pdev->domain, msi->arch.pirq);
+        spin_unlock(&pdev->domain->event_lock);
+        pcidevs_unlock();
+        msi->arch.pirq = INVALID_PIRQ;
+        return rc;
+    }
+    pcidevs_unlock();
+
+    return 0;
+}
+
 static int vpci_msi_enable(const struct pci_dev *pdev, uint32_t data,
                            uint64_t address, unsigned int nr,
                            paddr_t table_base, uint32_t mask)
diff --git a/xen/drivers/vpci/msi.c b/xen/drivers/vpci/msi.c
index ad26c38a92..8f15ad7bf2 100644
--- a/xen/drivers/vpci/msi.c
+++ b/xen/drivers/vpci/msi.c
@@ -87,8 +87,7 @@ static void update_msi(const struct pci_dev *pdev, struct vpci_msi *msi)
     if ( !msi->enabled )
         return;
 
-    vpci_msi_arch_disable(msi, pdev);
-    if ( vpci_msi_arch_enable(msi, pdev, msi->vectors) )
+    if ( vpci_msi_arch_update(msi, pdev) )
         msi->enabled = false;
 }
 
diff --git a/xen/include/xen/vpci.h b/xen/include/xen/vpci.h
index 72d2225a97..af2b8580ee 100644
--- a/xen/include/xen/vpci.h
+++ b/xen/include/xen/vpci.h
@@ -159,6 +159,8 @@ int __must_check vpci_msi_arch_enable(struct vpci_msi *msi,
                                       const struct pci_dev *pdev,
                                       unsigned int vectors);
 void vpci_msi_arch_disable(struct vpci_msi *msi, const struct pci_dev *pdev);
+int __must_check vpci_msi_arch_update(struct vpci_msi *msi,
+                                      const struct pci_dev *pdev);
 void vpci_msi_arch_init(struct vpci_msi *msi);
 void vpci_msi_arch_print(const struct vpci_msi *msi);