Since 45d3b59e8c45 ("kvm tools: Increase amount of possible interrupts
per PCI device"), the number of MSI-S has gone from 4 to 33.However, the corresponding storage hasn't been upgraded, and writing to the MSI-X table is a pretty risky business. Now that the Linux kernel writes to *all* MSI-X entries before doing anything else with the device, kvmtool dies a horrible death. Fix it by properly defining the size of the MSI-X bar, and make Linux great again. This includes some fixes the PBA region decoding, as well as minor cleanups to make this code a bit more maintainable. Signed-off-by: Marc Zyngier <[email protected]> --- virtio/pci.c | 42 ++++++++++++++++++++++++++++++------------ 1 file changed, 30 insertions(+), 12 deletions(-) diff --git a/virtio/pci.c b/virtio/pci.c index eb91f512..41085291 100644 --- a/virtio/pci.c +++ b/virtio/pci.c @@ -7,6 +7,7 @@ #include "kvm/irq.h" #include "kvm/virtio.h" #include "kvm/ioeventfd.h" +#include "kvm/util.h" #include <sys/ioctl.h> #include <linux/virtio_pci.h> @@ -14,6 +15,13 @@ #include <assert.h> #include <string.h> +#define ALIGN_UP(x, s) ALIGN((x) + (s) - 1, (s)) +#define VIRTIO_NR_MSIX (VIRTIO_PCI_MAX_VQ + VIRTIO_PCI_MAX_CONFIG) +#define VIRTIO_MSIX_TABLE_SIZE (VIRTIO_NR_MSIX * 16) +#define VIRTIO_MSIX_PBA_SIZE (ALIGN_UP(VIRTIO_MSIX_TABLE_SIZE, 64) / 8) +#define VIRTIO_MSIX_BAR_SIZE (1UL << fls_long(VIRTIO_MSIX_TABLE_SIZE + \ + VIRTIO_MSIX_PBA_SIZE)) + static u16 virtio_pci__port_addr(struct virtio_pci *vpci) { return pci__bar_address(&vpci->pci_hdr, 0); @@ -333,18 +341,27 @@ static void virtio_pci__msix_mmio_callback(struct kvm_cpu *vcpu, struct virtio_pci *vpci = vdev->virtio; struct msix_table *table; u32 msix_io_addr = virtio_pci__msix_io_addr(vpci); + u32 pba_offset; int vecnum; size_t offset; - if (addr > msix_io_addr + PCI_IO_SIZE) { + BUILD_BUG_ON(VIRTIO_NR_MSIX > (sizeof(vpci->msix_pba) * 8)); + + pba_offset = vpci->pci_hdr.msix.pba_offset & ~PCI_MSIX_TABLE_BIR; + if (addr >= msix_io_addr + pba_offset) { + /* Read access to PBA */ if (is_write) return; - table = (struct msix_table *)&vpci->msix_pba; - offset = addr - (msix_io_addr + PCI_IO_SIZE); - } else { - table = vpci->msix_table; - offset = addr - msix_io_addr; + offset = addr - (msix_io_addr + pba_offset); + if ((offset + len) > sizeof (vpci->msix_pba)) + return; + memcpy(data, (void *)&vpci->msix_pba + offset, len); + return; } + + table = vpci->msix_table; + offset = addr - msix_io_addr; + vecnum = offset / sizeof(struct msix_table); offset = offset % sizeof(struct msix_table); @@ -520,7 +537,7 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev, port_addr = pci_get_io_port_block(PCI_IO_SIZE); mmio_addr = pci_get_mmio_block(PCI_IO_SIZE); - msix_io_block = pci_get_mmio_block(PCI_IO_SIZE * 2); + msix_io_block = pci_get_mmio_block(VIRTIO_MSIX_BAR_SIZE); vpci->pci_hdr = (struct pci_device_header) { .vendor_id = cpu_to_le16(PCI_VENDOR_ID_REDHAT_QUMRANET), @@ -543,7 +560,7 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev, .capabilities = (void *)&vpci->pci_hdr.msix - (void *)&vpci->pci_hdr, .bar_size[0] = cpu_to_le32(PCI_IO_SIZE), .bar_size[1] = cpu_to_le32(PCI_IO_SIZE), - .bar_size[2] = cpu_to_le32(PCI_IO_SIZE*2), + .bar_size[2] = cpu_to_le32(VIRTIO_MSIX_BAR_SIZE), }; r = pci__register_bar_regions(kvm, &vpci->pci_hdr, @@ -560,8 +577,9 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev, vpci->pci_hdr.msix.cap = PCI_CAP_ID_MSIX; vpci->pci_hdr.msix.next = 0; /* - * We at most have VIRTIO_PCI_MAX_VQ entries for virt queue, - * VIRTIO_PCI_MAX_CONFIG entries for config. + * We at most have VIRTIO_NR_MSIX entries (VIRTIO_PCI_MAX_VQ + * entries for virt queue, VIRTIO_PCI_MAX_CONFIG entries for + * config). * * To quote the PCI spec: * @@ -570,11 +588,11 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev, * For example, a returned value of "00000000011" * indicates a table size of 4. */ - vpci->pci_hdr.msix.ctrl = cpu_to_le16(VIRTIO_PCI_MAX_VQ + VIRTIO_PCI_MAX_CONFIG - 1); + vpci->pci_hdr.msix.ctrl = cpu_to_le16(VIRTIO_NR_MSIX - 1); /* Both table and PBA are mapped to the same BAR (2) */ vpci->pci_hdr.msix.table_offset = cpu_to_le32(2); - vpci->pci_hdr.msix.pba_offset = cpu_to_le32(2 | PCI_IO_SIZE); + vpci->pci_hdr.msix.pba_offset = cpu_to_le32(2 | VIRTIO_MSIX_TABLE_SIZE); vpci->config_vector = 0; if (irq__can_signal_msi(kvm)) -- 2.30.2 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
