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Date: Tue, 16 Nov 2010 10:54:21 -0700
From: Alex Williamson <alex.williamson@...hat.com>
To: Tom Lyon <pugs@...co.com>
Cc: linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
kvm@...r.kernel.org
Subject: Re: [PATCH] vfio: fix config virtualization, esp command byte
On Tue, 2010-11-09 at 17:09 -0800, Tom Lyon wrote:
> Cleans up config space virtualization, especialy handling of bytes
> which have some virtual and some real bits, like PCI_COMMAND.
>
> Alex, I hope you can test this with your setups.
Sorry for the delay. FWIW, I'm not having much luck with this, I'll try
to debug the problem. Thanks,
Alex
> Signed-off-by: Tom Lyon <pugs@...co.com>
> ---
> drivers/vfio/vfio_pci_config.c | 166 +++++++++++++---------------------------
> 1 files changed, 53 insertions(+), 113 deletions(-)
>
> diff --git a/drivers/vfio/vfio_pci_config.c b/drivers/vfio/vfio_pci_config.c
> index 8304316..7132ac4 100644
> --- a/drivers/vfio/vfio_pci_config.c
> +++ b/drivers/vfio/vfio_pci_config.c
> @@ -745,6 +745,8 @@ static int vfio_virt_init(struct vfio_dev *vdev)
> */
> static void vfio_bar_restore(struct vfio_dev *vdev)
> {
> + if (vdev->pdev->is_virtfn)
> + return;
> printk(KERN_WARNING "%s: reset recovery - restoring bars\n", __func__);
>
> #define do_bar(off, which) \
> @@ -815,26 +817,15 @@ static inline int vfio_read_config_byte(struct vfio_dev *vdev,
> static inline int vfio_write_config_byte(struct vfio_dev *vdev,
> int pos, u8 val)
> {
> - vdev->vconfig[pos] = val;
> return pci_user_write_config_byte(vdev->pdev, pos, val);
> }
>
> /* handle virtualized fields in the basic config space */
> -static u8 vfio_virt_basic(struct vfio_dev *vdev, int write,
> - u16 pos, u16 off, u8 val, u8 newval)
> +static void vfio_virt_basic(struct vfio_dev *vdev, int write, u16 pos, u8 *rbp)
> {
> - switch (off) {
> - /*
> - * vendor and device are virt because they don't
> - * show up otherwise for sr-iov vfs
> - */
> - case PCI_VENDOR_ID:
> - case PCI_VENDOR_ID + 1:
> - case PCI_DEVICE_ID:
> - case PCI_DEVICE_ID + 1:
> - /* read only */
> - val = vdev->vconfig[pos];
> - break;
> + u8 val;
> +
> + switch (pos) {
> case PCI_COMMAND:
> /*
> * If the real mem or IO enable bits are zero
> @@ -842,100 +833,58 @@ static u8 vfio_virt_basic(struct vfio_dev *vdev, int write,
> * Restore the real BARs before allowing those
> * bits to re-enable
> */
> + val = vdev->vconfig[pos];
> if (vdev->pdev->is_virtfn)
> val |= PCI_COMMAND_MEMORY;
> if (write) {
> - int upd = 0;
> -
> - upd = (newval & PCI_COMMAND_MEMORY) >
> - (val & PCI_COMMAND_MEMORY);
> - upd += (newval & PCI_COMMAND_IO) >
> - (val & PCI_COMMAND_IO);
> - if (upd)
> - vfio_bar_restore(vdev);
> - vfio_write_config_byte(vdev, pos, newval);
> - }
> - break;
> - case PCI_BASE_ADDRESS_0:
> - case PCI_BASE_ADDRESS_0+1:
> - case PCI_BASE_ADDRESS_0+2:
> - case PCI_BASE_ADDRESS_0+3:
> - case PCI_BASE_ADDRESS_1:
> - case PCI_BASE_ADDRESS_1+1:
> - case PCI_BASE_ADDRESS_1+2:
> - case PCI_BASE_ADDRESS_1+3:
> - case PCI_BASE_ADDRESS_2:
> - case PCI_BASE_ADDRESS_2+1:
> - case PCI_BASE_ADDRESS_2+2:
> - case PCI_BASE_ADDRESS_2+3:
> - case PCI_BASE_ADDRESS_3:
> - case PCI_BASE_ADDRESS_3+1:
> - case PCI_BASE_ADDRESS_3+2:
> - case PCI_BASE_ADDRESS_3+3:
> - case PCI_BASE_ADDRESS_4:
> - case PCI_BASE_ADDRESS_4+1:
> - case PCI_BASE_ADDRESS_4+2:
> - case PCI_BASE_ADDRESS_4+3:
> - case PCI_BASE_ADDRESS_5:
> - case PCI_BASE_ADDRESS_5+1:
> - case PCI_BASE_ADDRESS_5+2:
> - case PCI_BASE_ADDRESS_5+3:
> - case PCI_ROM_ADDRESS:
> - case PCI_ROM_ADDRESS+1:
> - case PCI_ROM_ADDRESS+2:
> - case PCI_ROM_ADDRESS+3:
> - if (write) {
> - vdev->vconfig[pos] = newval;
> - vdev->bardirty = 1;
> - } else {
> - if (vdev->bardirty)
> - vfio_bar_fixup(vdev);
> - val = vdev->vconfig[pos];
> +
> + if (((val & PCI_COMMAND_MEMORY) >
> + (*rbp & PCI_COMMAND_MEMORY)) ||
> + ((val & PCI_COMMAND_IO) >
> + (*rbp & PCI_COMMAND_IO)))
> + vfio_bar_restore(vdev);
> + *rbp &= ~(PCI_COMMAND_MEMORY + PCI_COMMAND_IO);
> + *rbp |= val & (PCI_COMMAND_MEMORY + PCI_COMMAND_IO);
> }
> + vdev->vconfig[pos] = val;
> break;
> - default:
> + case PCI_BASE_ADDRESS_0 ... PCI_BASE_ADDRESS_5 + 3:
> + case PCI_ROM_ADDRESS ... PCI_ROM_ADDRESS + 3:
> if (write)
> - vdev->vconfig[pos] = newval;
> - else
> - val = vdev->vconfig[pos];
> + vdev->bardirty = 1;
> + else if (vdev->bardirty)
> + vfio_bar_fixup(vdev);
> break;
> }
> - return val;
> }
>
> /*
> * handle virtualized fields in msi capability
> * easy, except for multiple-msi fields in flags byte
> */
> -static u8 vfio_virt_msi(struct vfio_dev *vdev, int write,
> - u16 pos, u16 off, u8 val, u8 newval)
> +static void vfio_virt_msi(struct vfio_dev *vdev, int write,
> + u16 pos, u16 off, u8 *rbp)
> {
> - if (off == PCI_MSI_FLAGS) {
> - u8 num;
> + u8 val;
> + u8 num;
>
> + val = vdev->vconfig[pos];
> + if (off == PCI_MSI_FLAGS) {
> if (write) {
> if (!vdev->ev_msi)
> - newval &= ~PCI_MSI_FLAGS_ENABLE;
> - num = (newval & PCI_MSI_FLAGS_QSIZE) >> 4;
> + val &= ~PCI_MSI_FLAGS_ENABLE;
> + num = (val & PCI_MSI_FLAGS_QSIZE) >> 4;
> if (num > vdev->msi_qmax)
> num = vdev->msi_qmax;
> - newval &= ~PCI_MSI_FLAGS_QSIZE;
> - newval |= num << 4;
> - vfio_write_config_byte(vdev, pos, newval);
> + val &= ~PCI_MSI_FLAGS_QSIZE;
> + val |= num << 4;
> + *rbp = val;
> } else {
> - if (vfio_read_config_byte(vdev, pos, &val) < 0)
> - return 0;
> val &= ~PCI_MSI_FLAGS_QMASK;
> val |= vdev->msi_qmax << 1;
> }
> - return val;
> }
> -
> - if (write)
> - vdev->vconfig[pos] = newval;
> - else
> - val = vdev->vconfig[pos];
> - return val;
> + vdev->vconfig[pos] = val;
> }
>
> static int vfio_config_rwbyte(int write,
> @@ -950,6 +899,7 @@ static int vfio_config_rwbyte(int write,
> struct perm_bits *perm;
> u8 wr, virt;
> int ret;
> + u8 realbits = 0;
>
> cap = map[pos];
> if (cap == 0xFF) { /* unknown region */
> @@ -989,7 +939,7 @@ static int vfio_config_rwbyte(int write,
> }
> if (write && !wr) /* no writeable bits */
> return 0;
> - if (!virt) {
> + if (!virt) { /* no virtual bits */
> if (write) {
> if (copy_from_user(&val, buf, 1))
> return -EFAULT;
> @@ -1018,54 +968,44 @@ static int vfio_config_rwbyte(int write,
> if (copy_from_user(&newval, buf, 1))
> return -EFAULT;
> }
> - /*
> - * We get here if there are some virt bits
> - * handle remaining real bits, if any
> - */
> - if (~virt) {
> - u8 rbits = (~virt) & wr;
>
> - ret = vfio_read_config_byte(vdev, pos, &val);
> + if (~virt) { /* mix of real and virt bits */
> + /* update vconfig with latest hw bits */
> + ret = vfio_read_config_byte(vdev, pos, &realbits);
> if (ret < 0)
> return ret;
> - if (write && rbits) {
> - val &= ~rbits;
> - val |= (newval & rbits);
> - vfio_write_config_byte(vdev, pos, val);
> - }
> + vdev->vconfig[pos] =
> + (vdev->vconfig[pos] & virt) | (realbits & ~virt);
> }
> +
> + /* update vconfig with writeable bits */
> + vdev->vconfig[pos] =
> + (vdev->vconfig[pos] & ~wr) | (newval & wr);
> +
> /*
> - * Now handle entirely virtual fields
> + * Now massage virtual fields
> */
> if (pos < PCI_CFG_SPACE_SIZE) {
> switch (cap) {
> case PCI_CAP_ID_BASIC: /* virtualize BARs */
> - val = vfio_virt_basic(vdev, write,
> - pos, off, val, newval);
> + vfio_virt_basic(vdev, write, pos, &realbits);
> break;
> case PCI_CAP_ID_MSI: /* virtualize (parts of) MSI */
> - val = vfio_virt_msi(vdev, write,
> - pos, off, val, newval);
> - break;
> - default:
> - if (write)
> - vdev->vconfig[pos] = newval;
> - else
> - val = vdev->vconfig[pos];
> + vfio_virt_msi(vdev, write, pos, off, &realbits);
> break;
> }
> } else {
> /* no virt fields yet in ecaps */
> switch (cap) { /* extended capabilities */
> default:
> - if (write)
> - vdev->vconfig[pos] = newval;
> - else
> - val = vdev->vconfig[pos];
> break;
> }
> }
> - if (!write && copy_to_user(buf, &val, 1))
> + if (write && ~virt) {
> + realbits = (realbits & virt) | (vdev->vconfig[pos] & ~virt);
> + vfio_write_config_byte(vdev, pos, realbits);
> + }
> + if (!write && copy_to_user(buf, &vdev->vconfig[pos], 1))
> return -EFAULT;
> return 0;
> }
--
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