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Re: [Qemu-devel] [PATCH for v1.0 1/3] msix: track function masked in pci
From: |
Cam Macdonell |
Subject: |
Re: [Qemu-devel] [PATCH for v1.0 1/3] msix: track function masked in pci device state |
Date: |
Fri, 2 Dec 2011 16:34:21 -0700 |
Based on a git bisect, this patch breaks msi-x interrupt delivery in
the ivshmem device.
On Mon, Nov 21, 2011 at 9:57 AM, Michael S. Tsirkin <address@hidden> wrote:
> Only go over the table when function is masked.
> This is not really important for qemu.git but helps
> fix a bug in qemu-kvm.git.
>
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
> hw/msix.c | 21 ++++++++++++++-------
> hw/pci.h | 2 ++
> 2 files changed, 16 insertions(+), 7 deletions(-)
>
> diff --git a/hw/msix.c b/hw/msix.c
> index b15bafc..63b41b9 100644
> --- a/hw/msix.c
> +++ b/hw/msix.c
> @@ -79,6 +79,7 @@ static int msix_add_config(struct PCIDevice *pdev, unsigned
> short nentries,
> /* Make flags bit writable. */
> pdev->wmask[config_offset + MSIX_CONTROL_OFFSET] |= MSIX_ENABLE_MASK |
> MSIX_MASKALL_MASK;
> + pdev->msix_function_masked = true;
> return 0;
iiuc, this masks the msix by default.
> }
>
> @@ -117,16 +118,11 @@ static void msix_clr_pending(PCIDevice *dev, int vector)
> *msix_pending_byte(dev, vector) &= ~msix_pending_mask(vector);
> }
>
> -static int msix_function_masked(PCIDevice *dev)
> -{
> - return dev->config[dev->msix_cap + MSIX_CONTROL_OFFSET] &
> MSIX_MASKALL_MASK;
> -}
> -
> static int msix_is_masked(PCIDevice *dev, int vector)
> {
> unsigned offset =
> vector * PCI_MSIX_ENTRY_SIZE + PCI_MSIX_ENTRY_VECTOR_CTRL;
> - return msix_function_masked(dev) ||
> + return dev->msix_function_masked ||
> dev->msix_table_page[offset] & PCI_MSIX_ENTRY_CTRL_MASKBIT;
> }
>
> @@ -138,24 +134,34 @@ static void msix_handle_mask_update(PCIDevice *dev, int
> vector)
> }
> }
>
> +static void msix_update_function_masked(PCIDevice *dev)
> +{
> + dev->msix_function_masked = !msix_enabled(dev) ||
> + (dev->config[dev->msix_cap + MSIX_CONTROL_OFFSET] &
> MSIX_MASKALL_MASK);
> +}
> +
> /* Handle MSI-X capability config write. */
> void msix_write_config(PCIDevice *dev, uint32_t addr,
> uint32_t val, int len)
> {
> unsigned enable_pos = dev->msix_cap + MSIX_CONTROL_OFFSET;
> int vector;
> + bool was_masked;
>
> if (!range_covers_byte(addr, len, enable_pos)) {
> return;
> }
>
> + was_masked = dev->msix_function_masked;
> + msix_update_function_masked(dev);
> +
> if (!msix_enabled(dev)) {
> return;
> }
>
> pci_device_deassert_intx(dev);
>
> - if (msix_function_masked(dev)) {
> + if (dev->msix_function_masked == was_masked) {
> return;
> }
So I believe my bug is due to the fact the new logic included in this
patch requires msix_write_config() to be called to unmask the vectors.
Virtio-pci calls msix_write_config(), but ivshmem does not (nor does
PCIe so I'm not sure if it's also affected).
I haven't been able to fix the bug yet, but I wanted to make sure I
was looking in the correct place. Any help of further explanation of
this patch would be greatly appreciated.
Sincerely,
Cam
>
> @@ -300,6 +306,7 @@ void msix_load(PCIDevice *dev, QEMUFile *f)
> msix_free_irq_entries(dev);
> qemu_get_buffer(f, dev->msix_table_page, n * PCI_MSIX_ENTRY_SIZE);
> qemu_get_buffer(f, dev->msix_table_page + MSIX_PAGE_PENDING, (n + 7) / 8);
> + msix_update_function_masked(dev);
> }
>
> /* Does device support MSI-X? */
> diff --git a/hw/pci.h b/hw/pci.h
> index 4b2e785..625e717 100644
> --- a/hw/pci.h
> +++ b/hw/pci.h
> @@ -178,6 +178,8 @@ struct PCIDevice {
> unsigned *msix_entry_used;
> /* Region including the MSI-X table */
> uint32_t msix_bar_size;
> + /* MSIX function mask set or MSIX disabled */
> + bool msix_function_masked;
> /* Version id needed for VMState */
> int32_t version_id;
>
> --
> 1.7.5.53.gc233e
>
>
- Re: [Qemu-devel] [PATCH for v1.0 1/3] msix: track function masked in pci device state,
Cam Macdonell <=