Re: [PATCH v2 5/6] kvm: add PV MMIO

Paolo Bonzini
2013-04-04T12:46:22Z

Il 04/04/2013 12:40, Michael S. Tsirkin ha scritto:
> Add an option for users to specify PV eventfd
> listeners, and utilize KVM's PV MMIO underneath.
> Upodate all callers.

I would like Avi to comment on this, because I think this is not the
"memory-API approved" way of doing things. You need KVM to define its
own AddressSpace, and make KVM's listener use
memory_region_to_address_space to figure out if it is for PV MMIO.

To handle accesses from TCG, the PV AddressSpace can simply have just an
alias to the actual MemoryRegion where the doorbell is.

Paolo

> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> hw/dataplane/hostmem.c | 1 +
> hw/ivshmem.c | 2 ++
> hw/pci-testdev.c | 2 ++
> hw/vhost.c | 4 ++--
> hw/virtio-pci.c | 4 ++--
> include/exec/memory.h | 10 ++++++++++
> kvm-all.c | 15 ++++++++++++---
> linux-headers/linux/kvm.h | 8 ++++++++
> memory.c | 9 +++++++--
> 9 files changed, 46 insertions(+), 9 deletions(-)
>
> diff --git a/hw/dataplane/hostmem.c b/hw/dataplane/hostmem.c
> index 380537e..41d43e7 100644
> --- a/hw/dataplane/hostmem.c
> +++ b/hw/dataplane/hostmem.c
> @@ -126,6 +126,7 @@ static void hostmem_listener_section_dummy(MemoryListener *listener,
>
> static void hostmem_listener_eventfd_dummy(MemoryListener *listener,
> MemoryRegionSection *section,
> + bool pv,
> bool match_data, uint64_t data,
> EventNotifier *e)
> {
> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
> index 68a2cf2..28e5978 100644
> --- a/hw/ivshmem.c
> +++ b/hw/ivshmem.c
> @@ -352,6 +352,7 @@ static void ivshmem_add_eventfd(IVShmemState *s, int posn, int i)
> memory_region_add_eventfd(&s->ivshmem_mmio,
> DOORBELL,
> 4,
> + false,
> true,
> (posn << 16) | i,
> &s->peers[posn].eventfds[i]);
> @@ -362,6 +363,7 @@ static void ivshmem_del_eventfd(IVShmemState *s, int posn, int i)
> memory_region_del_eventfd(&s->ivshmem_mmio,
> DOORBELL,
> 4,
> + false,
> true,
> (posn << 16) | i,
> &s->peers[posn].eventfds[i]);
> diff --git a/hw/pci-testdev.c b/hw/pci-testdev.c
> index 9486624..f0ebf99 100644
> --- a/hw/pci-testdev.c
> +++ b/hw/pci-testdev.c
> @@ -80,6 +80,7 @@ static int pci_testdev_start(IOTest *test)
> memory_region_add_eventfd(test->mr,
> le32_to_cpu(test->hdr->offset),
> test->size,
> + false,
> test->match_data,
> test->hdr->data,
> &test->notifier);
> @@ -94,6 +95,7 @@ static void pci_testdev_stop(IOTest *test)
> memory_region_del_eventfd(test->mr,
> le32_to_cpu(test->hdr->offset),
> test->size,
> + false,
> test->match_data,
> test->hdr->data,
> &test->notifier);
> diff --git a/hw/vhost.c b/hw/vhost.c
> index 4d6aee3..9ad7101 100644
> --- a/hw/vhost.c
> +++ b/hw/vhost.c
> @@ -750,13 +750,13 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev,
> }
>
> static void vhost_eventfd_add(MemoryListener *listener,
> - MemoryRegionSection *section,
> + MemoryRegionSection *section, bool pv,
> bool match_data, uint64_t data, EventNotifier *e)
> {
> }
>
> static void vhost_eventfd_del(MemoryListener *listener,
> - MemoryRegionSection *section,
> + MemoryRegionSection *section, bool pv,
> bool match_data, uint64_t data, EventNotifier *e)
> {
> }
> diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
> index 19965e5..f9ff994 100644
> --- a/hw/virtio-pci.c
> +++ b/hw/virtio-pci.c
> @@ -189,10 +189,10 @@ static int virtio_pci_set_host_notifier_internal(VirtIOPCIProxy *proxy,
> }
> virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
> memory_region_add_eventfd(&proxy->bar, VIRTIO_PCI_QUEUE_NOTIFY, 2,
> - true, n, notifier);
> + false, true, n, notifier);
> } else {
> memory_region_del_eventfd(&proxy->bar, VIRTIO_PCI_QUEUE_NOTIFY, 2,
> - true, n, notifier);
> + false, true, n, notifier);
> virtio_queue_set_host_notifier_fd_handler(vq, false, false);
> event_notifier_cleanup(notifier);
> }
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index 2322732..3612004 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -215,8 +215,10 @@ struct MemoryListener {
> void (*log_global_start)(MemoryListener *listener);
> void (*log_global_stop)(MemoryListener *listener);
> void (*eventfd_add)(MemoryListener *listener, MemoryRegionSection *section,
> + bool pv,
> bool match_data, uint64_t data, EventNotifier *e);
> void (*eventfd_del)(MemoryListener *listener, MemoryRegionSection *section,
> + bool pv,
> bool match_data, uint64_t data, EventNotifier *e);
> void (*coalesced_mmio_add)(MemoryListener *listener, MemoryRegionSection *section,
> hwaddr addr, hwaddr len);
> @@ -594,6 +596,9 @@ void memory_region_clear_flush_coalesced(MemoryRegion *mr);
> * @mr: the memory region being updated.
> * @addr: the address within @mr that is to be monitored
> * @size: the size of the access to trigger the eventfd
> + * @pv: set if Guest can promise us that all accesses touching this address
> + * are writes of specified length, starting at the specified address.
> + * If not - it's a Guest bug. Might give faster access.
> * @match_data: whether to match against @data, instead of just @addr
> * @data: the data to match against the guest write
> * @fd: the eventfd to be triggered when @addr, @size, and @data all match.
> @@ -601,6 +606,7 @@ void memory_region_clear_flush_coalesced(MemoryRegion *mr);
> void memory_region_add_eventfd(MemoryRegion *mr,
> hwaddr addr,
> unsigned size,
> + bool pv,
> bool match_data,
> uint64_t data,
> EventNotifier *e);
> @@ -614,6 +620,9 @@ void memory_region_add_eventfd(MemoryRegion *mr,
> * @mr: the memory region being updated.
> * @addr: the address within @mr that is to be monitored
> * @size: the size of the access to trigger the eventfd
> + * @pv: set if Guest can promise us that all accesses touching this address
> + * are writes of specified length, starting at the specified address.
> + * If not - it's a Guest bug. Might give faster access.
> * @match_data: whether to match against @data, instead of just @addr
> * @data: the data to match against the guest write
> * @fd: the eventfd to be triggered when @addr, @size, and @data all match.
> @@ -621,6 +630,7 @@ void memory_region_add_eventfd(MemoryRegion *mr,
> void memory_region_del_eventfd(MemoryRegion *mr,
> hwaddr addr,
> unsigned size,
> + bool pv,
> bool match_data,
> uint64_t data,
> EventNotifier *e);
> diff --git a/kvm-all.c b/kvm-all.c
> index ce823f9..59835ca 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -500,7 +500,7 @@ int kvm_check_extension(KVMState *s, unsigned int extension)
> return ret;
> }
>
> -static int kvm_set_ioeventfd_mmio(int fd, uint32_t addr, uint32_t val,
> +static int kvm_set_ioeventfd_mmio(int fd, uint32_t addr, uint32_t val, bool pv,
> bool assign, uint32_t size, bool datamatch)
> {
> int ret;
> @@ -518,6 +518,11 @@ static int kvm_set_ioeventfd_mmio(int fd, uint32_t addr, uint32_t val,
>
> if (datamatch) {
> iofd.flags |= KVM_IOEVENTFD_FLAG_DATAMATCH;
> + /* Kernel doesn't support data match with PV MMIO. */
> + pv = false;
> + }
> + if (pv) {
> + iofd.flags |= KVM_IOEVENTFD_FLAG_PV_MMIO;
> }
> if (!assign) {
> iofd.flags |= KVM_IOEVENTFD_FLAG_DEASSIGN;
> @@ -802,6 +807,7 @@ static void kvm_log_global_stop(struct MemoryListener *listener)
>
> static void kvm_mem_ioeventfd_add(MemoryListener *listener,
> MemoryRegionSection *section,
> + bool pv,
> bool match_data, uint64_t data,
> EventNotifier *e)
> {
> @@ -809,7 +815,7 @@ static void kvm_mem_ioeventfd_add(MemoryListener *listener,
> int r;
>
> r = kvm_set_ioeventfd_mmio(fd, section->offset_within_address_space,
> - data, true, section->size, match_data);
> + data, pv, true, section->size, match_data);
> if (r < 0) {
> abort();
> }
> @@ -817,6 +823,7 @@ static void kvm_mem_ioeventfd_add(MemoryListener *listener,
>
> static void kvm_mem_ioeventfd_del(MemoryListener *listener,
> MemoryRegionSection *section,
> + bool pv,
> bool match_data, uint64_t data,
> EventNotifier *e)
> {
> @@ -824,7 +831,7 @@ static void kvm_mem_ioeventfd_del(MemoryListener *listener,
> int r;
>
> r = kvm_set_ioeventfd_mmio(fd, section->offset_within_address_space,
> - data, false, section->size, match_data);
> + data, pv, false, section->size, match_data);
> if (r < 0) {
> abort();
> }
> @@ -832,6 +839,7 @@ static void kvm_mem_ioeventfd_del(MemoryListener *listener,
>
> static void kvm_io_ioeventfd_add(MemoryListener *listener,
> MemoryRegionSection *section,
> + bool pv,
> bool match_data, uint64_t data,
> EventNotifier *e)
> {
> @@ -847,6 +855,7 @@ static void kvm_io_ioeventfd_add(MemoryListener *listener,
>
> static void kvm_io_ioeventfd_del(MemoryListener *listener,
> MemoryRegionSection *section,
> + bool pv,
> bool match_data, uint64_t data,
> EventNotifier *e)
>
> diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
> index caca979..871cc0a 100644
> --- a/linux-headers/linux/kvm.h
> +++ b/linux-headers/linux/kvm.h
> @@ -449,11 +449,19 @@ enum {
> kvm_ioeventfd_flag_nr_datamatch,
> kvm_ioeventfd_flag_nr_pio,
> kvm_ioeventfd_flag_nr_deassign,
> + kvm_ioeventfd_flag_nr_pv_mmio,
> kvm_ioeventfd_flag_nr_max,
> };
>
> #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch)
> #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio)
> +/*
> + * PV_MMIO - Guest can promise us that all accesses touching this address
> + * are writes of specified length, starting at the specified address.
> + * If not - it's a Guest bug.
> + * Can not be used together with either PIO or DATAMATCH.
> + */
> +#define KVM_IOEVENTFD_FLAG_PV_MMIO (1 << kvm_ioeventfd_flag_nr_pv_mmio)
> #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign)
>
> #define KVM_IOEVENTFD_VALID_FLAG_MASK ((1 << kvm_ioeventfd_flag_nr_max) - 1)
> diff --git a/memory.c b/memory.c
> index 92a2196..5a64b3c 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -162,6 +162,7 @@ struct CoalescedMemoryRange {
>
> struct MemoryRegionIoeventfd {
> AddrRange addr;
> + bool pv;
> bool match_data;
> uint64_t data;
> EventNotifier *e;
> @@ -600,7 +601,7 @@ static void address_space_add_del_ioeventfds(AddressSpace *as,
> .offset_within_address_space = int128_get64(fd->addr.start),
> .size = int128_get64(fd->addr.size),
> };
> - MEMORY_LISTENER_CALL(eventfd_del, Forward, &section,
> + MEMORY_LISTENER_CALL(eventfd_del, Forward, &section, fd->pv,
> fd->match_data, fd->data, fd->e);
> ++iold;
> } else if (inew < fds_new_nb
> @@ -613,7 +614,7 @@ static void address_space_add_del_ioeventfds(AddressSpace *as,
> .offset_within_address_space = int128_get64(fd->addr.start),
> .size = int128_get64(fd->addr.size),
> };
> - MEMORY_LISTENER_CALL(eventfd_add, Reverse, &section,
> + MEMORY_LISTENER_CALL(eventfd_add, Reverse, &section, fd->pv,
> fd->match_data, fd->data, fd->e);
> ++inew;
> } else {
> @@ -1243,6 +1244,7 @@ void memory_region_clear_flush_coalesced(MemoryRegion *mr)
> void memory_region_add_eventfd(MemoryRegion *mr,
> hwaddr addr,
> unsigned size,
> + bool pv,
> bool match_data,
> uint64_t data,
> EventNotifier *e)
> @@ -1250,6 +1252,7 @@ void memory_region_add_eventfd(MemoryRegion *mr,
> MemoryRegionIoeventfd mrfd = {
> .addr.start = int128_make64(addr),
> .addr.size = int128_make64(size),
> + .pv = pv,
> .match_data = match_data,
> .data = data,
> .e = e,
> @@ -1276,6 +1279,7 @@ void memory_region_add_eventfd(MemoryRegion *mr,
> void memory_region_del_eventfd(MemoryRegion *mr,
> hwaddr addr,
> unsigned size,
> + bool pv,
> bool match_data,
> uint64_t data,
> EventNotifier *e)
> @@ -1283,6 +1287,7 @@ void memory_region_del_eventfd(MemoryRegion *mr,
> MemoryRegionIoeventfd mrfd = {
> .addr.start = int128_make64(addr),
> .addr.size = int128_make64(size),
> + .pv = pv,
> .match_data = match_data,
> .data = data,
> .e = e,
>