On 26/03/2020 15:24, Alexandru Elisei wrote:
Hi,
> From: Alexandru Elisei <alexandru.elisei@xxxxxxxxx>
>
> Implement callbacks for activating and deactivating emulation for a BAR
> region. This is in preparation for allowing a guest operating system to
> enable and disable access to I/O or memory space, or to reassign the
> BARs.
>
> The emulated vesa device framebuffer isn't designed to allow stopping and
> restarting at arbitrary points in the guest execution. Furthermore, on x86,
> the kernel will not change the BAR addresses, which on bare metal are
> programmed by the firmware, so take the easy way out and refuse to
> activate/deactivate emulation for the BAR regions. We also take this
> opportunity to make the vesa emulation code more consistent by moving all
> static variable definitions in one place, at the top of the file.
>
> Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
> ---
> hw/vesa.c | 70 ++++++++++++++++++++------------
> include/kvm/pci.h | 18 ++++++++-
> pci.c | 44 ++++++++++++++++++++
> vfio/pci.c | 100 ++++++++++++++++++++++++++++++++++++++--------
> virtio/pci.c | 90 ++++++++++++++++++++++++++++++-----------
> 5 files changed, 254 insertions(+), 68 deletions(-)
>
> diff --git a/hw/vesa.c b/hw/vesa.c
> index 8071ad153f27..31c2d16ae4de 100644
> --- a/hw/vesa.c
> +++ b/hw/vesa.c
> @@ -18,6 +18,31 @@
> #include <inttypes.h>
> #include <unistd.h>
>
> +static struct pci_device_header vesa_pci_device = {
> + .vendor_id = cpu_to_le16(PCI_VENDOR_ID_REDHAT_QUMRANET),
> + .device_id = cpu_to_le16(PCI_DEVICE_ID_VESA),
> + .header_type = PCI_HEADER_TYPE_NORMAL,
> + .revision_id = 0,
> + .class[2] = 0x03,
> + .subsys_vendor_id = cpu_to_le16(PCI_SUBSYSTEM_VENDOR_ID_REDHAT_QUMRANET),
> + .subsys_id = cpu_to_le16(PCI_SUBSYSTEM_ID_VESA),
> + .bar[1] = cpu_to_le32(VESA_MEM_ADDR | PCI_BASE_ADDRESS_SPACE_MEMORY),
> + .bar_size[1] = VESA_MEM_SIZE,
> +};
> +
> +static struct device_header vesa_device = {
> + .bus_type = DEVICE_BUS_PCI,
> + .data = &vesa_pci_device,
> +};
> +
> +static struct framebuffer vesafb = {
> + .width = VESA_WIDTH,
> + .height = VESA_HEIGHT,
> + .depth = VESA_BPP,
> + .mem_addr = VESA_MEM_ADDR,
> + .mem_size = VESA_MEM_SIZE,
> +};
> +
> static bool vesa_pci_io_in(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port, void *data, int size)
> {
> return true;
> @@ -33,24 +58,19 @@ static struct ioport_operations vesa_io_ops = {
> .io_out = vesa_pci_io_out,
> };
>
> -static struct pci_device_header vesa_pci_device = {
> - .vendor_id = cpu_to_le16(PCI_VENDOR_ID_REDHAT_QUMRANET),
> - .device_id = cpu_to_le16(PCI_DEVICE_ID_VESA),
> - .header_type = PCI_HEADER_TYPE_NORMAL,
> - .revision_id = 0,
> - .class[2] = 0x03,
> - .subsys_vendor_id = cpu_to_le16(PCI_SUBSYSTEM_VENDOR_ID_REDHAT_QUMRANET),
> - .subsys_id = cpu_to_le16(PCI_SUBSYSTEM_ID_VESA),
> - .bar[1] = cpu_to_le32(VESA_MEM_ADDR | PCI_BASE_ADDRESS_SPACE_MEMORY),
> - .bar_size[1] = VESA_MEM_SIZE,
> -};
> -
> -static struct device_header vesa_device = {
> - .bus_type = DEVICE_BUS_PCI,
> - .data = &vesa_pci_device,
> -};
> +static int vesa__bar_activate(struct kvm *kvm, struct pci_device_header *pci_hdr,
> + int bar_num, void *data)
> +{
> + /* We don't support remapping of the framebuffer. */
> + return 0;
> +}
>
> -static struct framebuffer vesafb;
> +static int vesa__bar_deactivate(struct kvm *kvm, struct pci_device_header *pci_hdr,
> + int bar_num, void *data)
> +{
> + /* We don't support remapping of the framebuffer. */
> + return -EINVAL;
> +}
>
> struct framebuffer *vesa__init(struct kvm *kvm)
> {
> @@ -73,6 +93,11 @@ struct framebuffer *vesa__init(struct kvm *kvm)
>
> vesa_pci_device.bar[0] = cpu_to_le32(vesa_base_addr | PCI_BASE_ADDRESS_SPACE_IO);
> vesa_pci_device.bar_size[0] = PCI_IO_SIZE;
> + r = pci__register_bar_regions(kvm, &vesa_pci_device, vesa__bar_activate,
> + vesa__bar_deactivate, NULL);
> + if (r < 0)
> + goto unregister_ioport;
> +
> r = device__register(&vesa_device);
> if (r < 0)
> goto unregister_ioport;
> @@ -87,15 +112,8 @@ struct framebuffer *vesa__init(struct kvm *kvm)
> if (r < 0)
> goto unmap_dev;
>
> - vesafb = (struct framebuffer) {
> - .width = VESA_WIDTH,
> - .height = VESA_HEIGHT,
> - .depth = VESA_BPP,
> - .mem = mem,
> - .mem_addr = VESA_MEM_ADDR,
> - .mem_size = VESA_MEM_SIZE,
> - .kvm = kvm,
> - };
> + vesafb.mem = mem;
> + vesafb.kvm = kvm;
> return fb__register(&vesafb);
>
> unmap_dev:
Those transformations look correct to me.
> diff --git a/include/kvm/pci.h b/include/kvm/pci.h
> index adb4b5c082d5..1d7d4c0cea5a 100644
> --- a/include/kvm/pci.h
> +++ b/include/kvm/pci.h
> @@ -89,12 +89,19 @@ struct pci_cap_hdr {
> u8 next;
> };
>
> +struct pci_device_header;
> +
> +typedef int (*bar_activate_fn_t)(struct kvm *kvm,
> + struct pci_device_header *pci_hdr,
> + int bar_num, void *data);
> +typedef int (*bar_deactivate_fn_t)(struct kvm *kvm,
> + struct pci_device_header *pci_hdr,
> + int bar_num, void *data);
> +
> #define PCI_BAR_OFFSET(b) (offsetof(struct pci_device_header, bar[b]))
> #define PCI_DEV_CFG_SIZE 256
> #define PCI_DEV_CFG_MASK (PCI_DEV_CFG_SIZE - 1)
>
> -struct pci_device_header;
> -
> struct pci_config_operations {
> void (*write)(struct kvm *kvm, struct pci_device_header *pci_hdr,
> u8 offset, void *data, int sz);
> @@ -136,6 +143,9 @@ struct pci_device_header {
>
> /* Private to lkvm */
> u32 bar_size[6];
> + bar_activate_fn_t bar_activate_fn;
> + bar_deactivate_fn_t bar_deactivate_fn;
> + void *data;
> struct pci_config_operations cfg_ops;
> /*
> * PCI INTx# are level-triggered, but virtual device often feature
> @@ -162,6 +172,10 @@ void pci__config_rd(struct kvm *kvm, union pci_config_address addr, void *data,
>
> void *pci_find_cap(struct pci_device_header *hdr, u8 cap_type);
>
> +int pci__register_bar_regions(struct kvm *kvm, struct pci_device_header *pci_hdr,
> + bar_activate_fn_t bar_activate_fn,
> + bar_deactivate_fn_t bar_deactivate_fn, void *data);
> +
> static inline bool __pci__memory_space_enabled(u16 command)
> {
> return command & PCI_COMMAND_MEMORY;
> diff --git a/pci.c b/pci.c
> index 611e2c0bf1da..4ace190898f2 100644
> --- a/pci.c
> +++ b/pci.c
> @@ -66,6 +66,11 @@ void pci__assign_irq(struct device_header *dev_hdr)
> pci_hdr->irq_type = IRQ_TYPE_EDGE_RISING;
> }
>
> +static bool pci_bar_is_implemented(struct pci_device_header *pci_hdr, int bar_num)
> +{
> + return pci__bar_size(pci_hdr, bar_num);
> +}
> +
> static void *pci_config_address_ptr(u16 port)
> {
> unsigned long offset;
> @@ -273,6 +278,45 @@ struct pci_device_header *pci__find_dev(u8 dev_num)
> return hdr->data;
> }
>
> +int pci__register_bar_regions(struct kvm *kvm, struct pci_device_header *pci_hdr,
> + bar_activate_fn_t bar_activate_fn,
> + bar_deactivate_fn_t bar_deactivate_fn, void *data)
> +{
> + int i, r;
> + bool has_bar_regions = false;
> +
> + assert(bar_activate_fn && bar_deactivate_fn);
> +
> + pci_hdr->bar_activate_fn = bar_activate_fn;
> + pci_hdr->bar_deactivate_fn = bar_deactivate_fn;
> + pci_hdr->data = data;
> +
> + for (i = 0; i < 6; i++) {
> + if (!pci_bar_is_implemented(pci_hdr, i))
> + continue;
> +
> + has_bar_regions = true;
> +
> + if (pci__bar_is_io(pci_hdr, i) &&
> + pci__io_space_enabled(pci_hdr)) {
> + r = bar_activate_fn(kvm, pci_hdr, i, data);
> + if (r < 0)
> + return r;
> + }
Indentation seems to be off here, I think the last 4 lines need to have
one tab removed.
> +
> + if (pci__bar_is_memory(pci_hdr, i) &&
> + pci__memory_space_enabled(pci_hdr)) {
> + r = bar_activate_fn(kvm, pci_hdr, i, data);
> + if (r < 0)
> + return r;
> + }
Same indentation issue here.
> + }
> +
> + assert(has_bar_regions);
Is assert() here really a good idea? I see that it makes sense for our
emulated devices, but is that a valid check for VFIO?
>From briefly looking I can't find a requirement for having at least one
valid BAR in general, and even if - I think we should rather return an
error than aborting the guest here - or ignore it altogether.
> +
> + return 0;
> +}
> +
> int pci__init(struct kvm *kvm)
> {
> int r;
> diff --git a/vfio/pci.c b/vfio/pci.c
> index 8b2a0c8dbac3..18e22a8c5320 100644
> --- a/vfio/pci.c
> +++ b/vfio/pci.c
> @@ -8,6 +8,8 @@
> #include <sys/resource.h>
> #include <sys/time.h>
>
> +#include <assert.h>
> +
> /* Wrapper around UAPI vfio_irq_set */
> union vfio_irq_eventfd {
> struct vfio_irq_set irq;
> @@ -446,6 +448,81 @@ out_unlock:
> mutex_unlock(&pdev->msi.mutex);
> }
>
> +static int vfio_pci_bar_activate(struct kvm *kvm,
> + struct pci_device_header *pci_hdr,
> + int bar_num, void *data)
> +{
> + struct vfio_device *vdev = data;
> + struct vfio_pci_device *pdev = &vdev->pci;
> + struct vfio_pci_msix_pba *pba = &pdev->msix_pba;
> + struct vfio_pci_msix_table *table = &pdev->msix_table;
> + struct vfio_region *region;
> + bool has_msix;
> + int ret;
> +
> + assert((u32)bar_num < vdev->info.num_regions);
> +
> + region = &vdev->regions[bar_num];
> + has_msix = pdev->irq_modes & VFIO_PCI_IRQ_MODE_MSIX;
> +
> + if (has_msix && (u32)bar_num == table->bar) {
> + ret = kvm__register_mmio(kvm, table->guest_phys_addr,
> + table->size, false,
> + vfio_pci_msix_table_access, pdev);
> + if (ret < 0 || table->bar != pba->bar)
I think this second expression deserves some comment.
If I understand correctly, this would register the PBA trap handler
separetely below if both the MSIX table and the PBA share a BAR?
> + goto out;
Is there any particular reason you are using goto here? I find it more
confusing if the "out:" label has just a return statement, without any
cleanup or lock dropping. Just a "return ret;" here would be much
cleaner I think. Same for other occassions in this function and
elsewhere in this patch.
Or do you plan on adding some code here later? I don't see it in this
series though.
> + }
> +
> + if (has_msix && (u32)bar_num == pba->bar) {
> + ret = kvm__register_mmio(kvm, pba->guest_phys_addr,
> + pba->size, false,
> + vfio_pci_msix_pba_access, pdev);
> + goto out;
> + }
> +
> + ret = vfio_map_region(kvm, vdev, region);
> +out:
> + return ret;
> +}
> +
> +static int vfio_pci_bar_deactivate(struct kvm *kvm,
> + struct pci_device_header *pci_hdr,
> + int bar_num, void *data)
> +{
> + struct vfio_device *vdev = data;
> + struct vfio_pci_device *pdev = &vdev->pci;
> + struct vfio_pci_msix_pba *pba = &pdev->msix_pba;
> + struct vfio_pci_msix_table *table = &pdev->msix_table;
> + struct vfio_region *region;
> + bool has_msix, success;
> + int ret;
> +
> + assert((u32)bar_num < vdev->info.num_regions);
> +
> + region = &vdev->regions[bar_num];
> + has_msix = pdev->irq_modes & VFIO_PCI_IRQ_MODE_MSIX;
> +
> + if (has_msix && (u32)bar_num == table->bar) {
> + success = kvm__deregister_mmio(kvm, table->guest_phys_addr);
> + /* kvm__deregister_mmio fails when the region is not found. */
> + ret = (success ? 0 : -ENOENT);
> + if (ret < 0 || table->bar!= pba->bar)
> + goto out;
> + }
> +
> + if (has_msix && (u32)bar_num == pba->bar) {
> + success = kvm__deregister_mmio(kvm, pba->guest_phys_addr);
> + ret = (success ? 0 : -ENOENT);
> + goto out;
> + }
> +
> + vfio_unmap_region(kvm, region);
> + ret = 0;
> +
> +out:
> + return ret;
> +}
> +
> static void vfio_pci_cfg_read(struct kvm *kvm, struct pci_device_header *pci_hdr,
> u8 offset, void *data, int sz)
> {
> @@ -805,12 +882,6 @@ static int vfio_pci_create_msix_table(struct kvm *kvm, struct vfio_device *vdev)
> ret = -ENOMEM;
> goto out_free;
> }
> - pba->guest_phys_addr = table->guest_phys_addr + table->size;
> -
> - ret = kvm__register_mmio(kvm, table->guest_phys_addr, table->size,
> - false, vfio_pci_msix_table_access, pdev);
> - if (ret < 0)
> - goto out_free;
>
> /*
> * We could map the physical PBA directly into the guest, but it's
> @@ -820,10 +891,7 @@ static int vfio_pci_create_msix_table(struct kvm *kvm, struct vfio_device *vdev)
> * between MSI-X table and PBA. For the sake of isolation, create a
> * virtual PBA.
> */
> - ret = kvm__register_mmio(kvm, pba->guest_phys_addr, pba->size, false,
> - vfio_pci_msix_pba_access, pdev);
> - if (ret < 0)
> - goto out_free;
> + pba->guest_phys_addr = table->guest_phys_addr + table->size;
>
> pdev->msix.entries = entries;
> pdev->msix.nr_entries = nr_entries;
> @@ -894,11 +962,6 @@ static int vfio_pci_configure_bar(struct kvm *kvm, struct vfio_device *vdev,
> region->guest_phys_addr = pci_get_mmio_block(map_size);
> }
>
> - /* Map the BARs into the guest or setup a trap region. */
> - ret = vfio_map_region(kvm, vdev, region);
> - if (ret)
> - return ret;
> -
> return 0;
> }
>
> @@ -945,7 +1008,12 @@ static int vfio_pci_configure_dev_regions(struct kvm *kvm,
> }
>
> /* We've configured the BARs, fake up a Configuration Space */
> - return vfio_pci_fixup_cfg_space(vdev);
> + ret = vfio_pci_fixup_cfg_space(vdev);
> + if (ret)
> + return ret;
> +
> + return pci__register_bar_regions(kvm, &pdev->hdr, vfio_pci_bar_activate,
> + vfio_pci_bar_deactivate, vdev);
> }
>
> /*
> diff --git a/virtio/pci.c b/virtio/pci.c
> index d111dc499f5e..598da699c241 100644
> --- a/virtio/pci.c
> +++ b/virtio/pci.c
> @@ -11,6 +11,7 @@
> #include <sys/ioctl.h>
> #include <linux/virtio_pci.h>
> #include <linux/byteorder.h>
> +#include <assert.h>
> #include <string.h>
>
> static u16 virtio_pci__port_addr(struct virtio_pci *vpci)
> @@ -462,6 +463,64 @@ static void virtio_pci__io_mmio_callback(struct kvm_cpu *vcpu,
> virtio_pci__data_out(vcpu, vdev, addr - mmio_addr, data, len);
> }
>
> +static int virtio_pci__bar_activate(struct kvm *kvm,
> + struct pci_device_header *pci_hdr,
> + int bar_num, void *data)
> +{
> + struct virtio_device *vdev = data;
> + u32 bar_addr, bar_size;
> + int r = -EINVAL;
> +
> + assert(bar_num <= 2);
> +
> + bar_addr = pci__bar_address(pci_hdr, bar_num);
> + bar_size = pci__bar_size(pci_hdr, bar_num);
> +
> + switch (bar_num) {
> + case 0:
> + r = ioport__register(kvm, bar_addr, &virtio_pci__io_ops,
> + bar_size, vdev);
> + if (r > 0)
> + r = 0;
> + break;
> + case 1:
> + r = kvm__register_mmio(kvm, bar_addr, bar_size, false,
> + virtio_pci__io_mmio_callback, vdev);
> + break;
> + case 2:
> + r = kvm__register_mmio(kvm, bar_addr, bar_size, false,
> + virtio_pci__msix_mmio_callback, vdev);
I think adding a break; here looks nicer.
Cheers,
Andre
> + }
> +
> + return r;
> +}
> +
> +static int virtio_pci__bar_deactivate(struct kvm *kvm,
> + struct pci_device_header *pci_hdr,
> + int bar_num, void *data)
> +{
> + u32 bar_addr;
> + bool success;
> + int r = -EINVAL;
> +
> + assert(bar_num <= 2);
> +
> + bar_addr = pci__bar_address(pci_hdr, bar_num);
> +
> + switch (bar_num) {
> + case 0:
> + r = ioport__unregister(kvm, bar_addr);
> + break;
> + case 1:
> + case 2:
> + success = kvm__deregister_mmio(kvm, bar_addr);
> + /* kvm__deregister_mmio fails when the region is not found. */
> + r = (success ? 0 : -ENOENT);
> + }
> +
> + return r;
> +}
> +
> int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
> int device_id, int subsys_id, int class)
> {
> @@ -476,23 +535,8 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
> BUILD_BUG_ON(!is_power_of_two(PCI_IO_SIZE));
>
> port_addr = pci_get_io_port_block(PCI_IO_SIZE);
> - r = ioport__register(kvm, port_addr, &virtio_pci__io_ops, PCI_IO_SIZE,
> - vdev);
> - if (r < 0)
> - return r;
> - port_addr = (u16)r;
> -
> mmio_addr = pci_get_mmio_block(PCI_IO_SIZE);
> - r = kvm__register_mmio(kvm, mmio_addr, PCI_IO_SIZE, false,
> - virtio_pci__io_mmio_callback, vdev);
> - if (r < 0)
> - goto free_ioport;
> -
> msix_io_block = pci_get_mmio_block(PCI_IO_SIZE * 2);
> - r = kvm__register_mmio(kvm, msix_io_block, PCI_IO_SIZE * 2, false,
> - virtio_pci__msix_mmio_callback, vdev);
> - if (r < 0)
> - goto free_mmio;
>
> vpci->pci_hdr = (struct pci_device_header) {
> .vendor_id = cpu_to_le16(PCI_VENDOR_ID_REDHAT_QUMRANET),
> @@ -518,6 +562,12 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
> .bar_size[2] = cpu_to_le32(PCI_IO_SIZE*2),
> };
>
> + r = pci__register_bar_regions(kvm, &vpci->pci_hdr,
> + virtio_pci__bar_activate,
> + virtio_pci__bar_deactivate, vdev);
> + if (r < 0)
> + return r;
> +
> vpci->dev_hdr = (struct device_header) {
> .bus_type = DEVICE_BUS_PCI,
> .data = &vpci->pci_hdr,
> @@ -548,20 +598,12 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
>
> r = device__register(&vpci->dev_hdr);
> if (r < 0)
> - goto free_msix_mmio;
> + return r;
>
> /* save the IRQ that device__register() has allocated */
> vpci->legacy_irq_line = vpci->pci_hdr.irq_line;
>
> return 0;
> -
> -free_msix_mmio:
> - kvm__deregister_mmio(kvm, msix_io_block);
> -free_mmio:
> - kvm__deregister_mmio(kvm, mmio_addr);
> -free_ioport:
> - ioport__unregister(kvm, port_addr);
> - return r;
> }
>
> int virtio_pci__reset(struct kvm *kvm, struct virtio_device *vdev)
>
