From 5ad31525c9aeed6d3a349799fe491b5a7c678049 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Roger=20Pau=20Monn=C3=A9?= Date: Tue, 22 Sep 2020 16:11:06 +0200 Subject: [PATCH] x86/msi: get rid of read_msi_msg MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit It's safer and faster to just use the cached last written (untranslated) MSI message stored in msi_desc for the single user that calls read_msi_msg. This also prevents relying on the data read from the device MSI registers in order to figure out the index into the IOMMU interrupt remapping table, which is not safe. This is part of XSA-337. Reported-by: Andrew Cooper Requested-by: Andrew Cooper Signed-off-by: Roger Pau Monné Reviewed-by: Jan Beulich --- xen/arch/x86/msi.c | 53 +--------------------------------------------- 1 file changed, 1 insertion(+), 52 deletions(-) diff --git a/xen/arch/x86/msi.c b/xen/arch/x86/msi.c index 161ee60dbe..6a00bc9312 100644 --- a/xen/arch/x86/msi.c +++ b/xen/arch/x86/msi.c @@ -185,54 +185,6 @@ void msi_compose_msg(unsigned vector, const cpumask_t *cpu_mask, struct msi_msg MSI_DATA_VECTOR(vector); } -static bool read_msi_msg(struct msi_desc *entry, struct msi_msg *msg) -{ - switch ( entry->msi_attrib.type ) - { - case PCI_CAP_ID_MSI: - { - struct pci_dev *dev = entry->dev; - int pos = entry->msi_attrib.pos; - uint16_t data; - - msg->address_lo = pci_conf_read32(dev->sbdf, - msi_lower_address_reg(pos)); - if ( entry->msi_attrib.is_64 ) - { - msg->address_hi = pci_conf_read32(dev->sbdf, - msi_upper_address_reg(pos)); - data = pci_conf_read16(dev->sbdf, msi_data_reg(pos, 1)); - } - else - { - msg->address_hi = 0; - data = pci_conf_read16(dev->sbdf, msi_data_reg(pos, 0)); - } - msg->data = data; - break; - } - case PCI_CAP_ID_MSIX: - { - void __iomem *base = entry->mask_base; - - if ( unlikely(!msix_memory_decoded(entry->dev, - entry->msi_attrib.pos)) ) - return false; - msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET); - msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET); - msg->data = readl(base + PCI_MSIX_ENTRY_DATA_OFFSET); - break; - } - default: - BUG(); - } - - if ( iommu_intremap ) - iommu_read_msi_from_ire(entry, msg); - - return true; -} - static int write_msi_msg(struct msi_desc *entry, struct msi_msg *msg) { entry->msg = *msg; @@ -304,10 +256,7 @@ void set_msi_affinity(struct irq_desc *desc, const cpumask_t *mask) ASSERT(spin_is_locked(&desc->lock)); - memset(&msg, 0, sizeof(msg)); - if ( !read_msi_msg(msi_desc, &msg) ) - return; - + msg = msi_desc->msg; msg.data &= ~MSI_DATA_VECTOR_MASK; msg.data |= MSI_DATA_VECTOR(desc->arch.vector); msg.address_lo &= ~MSI_ADDR_DEST_ID_MASK; -- 2.30.2