* Jagannathan Raman (jag.ra...@oracle.com) wrote:
> Add memory-listener object which is used to keep the view of the RAM
> in sync between QEMU and remote process.
> A MemoryListener is registered for system-memory AddressSpace. The
> listener sends SYNC_SYSMEM message to the remote process when memory
> listener commits the changes to memory, the remote process receives
> the message and processes it in the handler for SYNC_SYSMEM message.
>
> TODO: No need to create object for remote memory listener.
>
> Signed-off-by: Jagannathan Raman <jag.ra...@oracle.com>
> Signed-off-by: John G Johnson <john.g.john...@oracle.com>
> Signed-off-by: Elena Ufimtseva <elena.ufimts...@oracle.com>
> ---
> Makefile.target | 3 +
> hw/proxy/memory-sync.c | 212
> +++++++++++++++++++++++++++++++++++++++++
> hw/proxy/qemu-proxy.c | 5 +
> include/hw/proxy/memory-sync.h | 37 +++++++
> include/hw/proxy/qemu-proxy.h | 5 +
> remote/remote-main.c | 11 +++
> 6 files changed, 273 insertions(+)
> create mode 100644 hw/proxy/memory-sync.c
> create mode 100644 include/hw/proxy/memory-sync.h
>
> diff --git a/Makefile.target b/Makefile.target
> index cfd36c1..271d883 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -127,6 +127,9 @@ obj-$(CONFIG_TCG) += fpu/softfloat.o
> obj-y += target/$(TARGET_BASE_ARCH)/
> obj-y += disas.o
> obj-$(call notempty,$(TARGET_XML_FILES)) += gdbstub-xml.o
> +ifeq ($(TARGET_NAME)-$(CONFIG_MPQEMU)-$(CONFIG_USER_ONLY), x86_64-y-)
> +obj-$(CONFIG_MPQEMU) += hw/proxy/memory-sync.o
> +endif
> LIBS := $(libs_cpu) $(LIBS)
>
> obj-$(CONFIG_PLUGIN) += plugins/
> diff --git a/hw/proxy/memory-sync.c b/hw/proxy/memory-sync.c
> new file mode 100644
> index 0000000..3edbb19
> --- /dev/null
> +++ b/hw/proxy/memory-sync.c
> @@ -0,0 +1,212 @@
> +/*
> + * Copyright © 2018, 2020 Oracle and/or its affiliates.
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + *
> + */
> +
> +#include <sys/types.h>
> +#include <stdio.h>
> +#include <string.h>
> +
> +#include "qemu/osdep.h"
> +#include "qemu/compiler.h"
> +#include "qemu/int128.h"
> +#include "qemu/range.h"
> +#include "exec/memory.h"
> +#include "exec/cpu-common.h"
> +#include "cpu.h"
> +#include "exec/ram_addr.h"
> +#include "exec/address-spaces.h"
> +#include "io/mpqemu-link.h"
> +#include "hw/proxy/memory-sync.h"
> +
> +static const TypeInfo remote_mem_sync_type_info = {
> + .name = TYPE_MEMORY_LISTENER,
> + .parent = TYPE_OBJECT,
> + .instance_size = sizeof(RemoteMemSync),
> +};
> +
> +static void remote_mem_sync_register_types(void)
> +{
> + type_register_static(&remote_mem_sync_type_info);
> +}
> +
> +type_init(remote_mem_sync_register_types)
> +
> +static void proxy_ml_begin(MemoryListener *listener)
> +{
> + RemoteMemSync *sync = container_of(listener, RemoteMemSync, listener);
> + int mrs;
> +
> + for (mrs = 0; mrs < sync->n_mr_sections; mrs++) {
> + memory_region_unref(sync->mr_sections[mrs].mr);
> + }
> +
> + g_free(sync->mr_sections);
> + sync->mr_sections = NULL;
> + sync->n_mr_sections = 0;
> +}
> +
> +static int get_fd_from_hostaddr(uint64_t host, ram_addr_t *offset)
> +{
> + MemoryRegion *mr;
> + ram_addr_t off;
> +
> + mr = memory_region_from_host((void *)(uintptr_t)host, &off);
Do you need to just check we found an 'mr' ?
> + if (offset) {
> + *offset = off;
> + }
> +
> + return memory_region_get_fd(mr);
> +}
> +
> +static bool proxy_mrs_can_merge(uint64_t host, uint64_t prev_host, size_t
> size)
> +{
> + bool merge;
> + int fd1, fd2;
> +
> + fd1 = get_fd_from_hostaddr(host, NULL);
> +
> + fd2 = get_fd_from_hostaddr(prev_host, NULL);
> +
> + merge = (fd1 == fd2);
> +
> + merge &= ((prev_host + size) == host);
It's interesting; I think the vhost code checks that the two mr's are
the same where you are checking for the same underlying fd - but I think
that's OK.
(I wonder if we need to check offset's within the fd's match up when
they're merged - since you added that offset feature in an earlier
patch?
That would also need checking in vhost_region_add_section)
> + return merge;
> +}
> +
> +static void proxy_ml_region_addnop(MemoryListener *listener,
> + MemoryRegionSection *section)
> +{
> + RemoteMemSync *sync = container_of(listener, RemoteMemSync, listener);
> + bool need_add = true;
> + uint64_t mrs_size, mrs_gpa, mrs_page;
> + uintptr_t mrs_host;
> + RAMBlock *mrs_rb;
> + MemoryRegionSection *prev_sec;
> +
> + if (!(memory_region_is_ram(section->mr) &&
> + !memory_region_is_rom(section->mr))) {
> + return;
> + }
> +
> + mrs_rb = section->mr->ram_block;
> + mrs_page = (uint64_t)qemu_ram_pagesize(mrs_rb);
> + mrs_size = int128_get64(section->size);
> + mrs_gpa = section->offset_within_address_space;
> + mrs_host = (uintptr_t)memory_region_get_ram_ptr(section->mr) +
> + section->offset_within_region;
> +
> + if (get_fd_from_hostaddr(mrs_host, NULL) <= 0) {
> + return;
> + }
> +
> + mrs_host = mrs_host & ~(mrs_page - 1);
> + mrs_gpa = mrs_gpa & ~(mrs_page - 1);
> + mrs_size = ROUND_UP(mrs_size, mrs_page);
OK, just note the more complex code in vhost_region_add_section for page
aligning regions that are needed for postcopy; I think that would be the
same if you wanted to do postcopy with remote processes.
> + if (sync->n_mr_sections) {
> + prev_sec = sync->mr_sections + (sync->n_mr_sections - 1);
> + uint64_t prev_gpa_start = prev_sec->offset_within_address_space;
> + uint64_t prev_size = int128_get64(prev_sec->size);
> + uint64_t prev_gpa_end = range_get_last(prev_gpa_start, prev_size);
> + uint64_t prev_host_start =
> + (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr) +
> + prev_sec->offset_within_region;
> + uint64_t prev_host_end = range_get_last(prev_host_start, prev_size);
> +
> + if (mrs_gpa <= (prev_gpa_end + 1)) {
> + if (mrs_gpa < prev_gpa_start) {
> + assert(0);
> + }
g_assert(mrs_gpa < prev_gpa_start);
> + if ((section->mr == prev_sec->mr) &&
> + proxy_mrs_can_merge(mrs_host, prev_host_start,
> + (mrs_gpa - prev_gpa_start))) {
> + uint64_t max_end = MAX(prev_host_end, mrs_host + mrs_size);
> + need_add = false;
> + prev_sec->offset_within_address_space =
> + MIN(prev_gpa_start, mrs_gpa);
> + prev_sec->offset_within_region =
> + MIN(prev_host_start, mrs_host) -
> + (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr);
> + prev_sec->size = int128_make64(max_end - MIN(prev_host_start,
> + mrs_host));
> + }
> + }
> + }
> +
> + if (need_add) {
> + ++sync->n_mr_sections;
> + sync->mr_sections = g_renew(MemoryRegionSection, sync->mr_sections,
> + sync->n_mr_sections);
> + sync->mr_sections[sync->n_mr_sections - 1] = *section;
> + sync->mr_sections[sync->n_mr_sections - 1].fv = NULL;
> + memory_region_ref(section->mr);
> + }
I'd add some tracing in this function; it's a nightmare to debug when it
does something unexpected.
> +}
> +
> +static void proxy_ml_commit(MemoryListener *listener)
> +{
> + RemoteMemSync *sync = container_of(listener, RemoteMemSync, listener);
> + MPQemuMsg msg;
> + MemoryRegionSection section;
> + ram_addr_t offset;
> + uintptr_t host_addr;
> + int region;
> +
> + memset(&msg, 0, sizeof(MPQemuMsg));
> +
> + msg.cmd = SYNC_SYSMEM;
> + msg.bytestream = 0;
> + msg.num_fds = sync->n_mr_sections;
> + msg.size = sizeof(msg.data1);
> + assert(msg.num_fds <= REMOTE_MAX_FDS);
> +
> + for (region = 0; region < sync->n_mr_sections; region++) {
> + section = sync->mr_sections[region];
> + msg.data1.sync_sysmem.gpas[region] =
> + section.offset_within_address_space;
> + msg.data1.sync_sysmem.sizes[region] = int128_get64(section.size);
> + host_addr = (uintptr_t)memory_region_get_ram_ptr(section.mr) +
> + section.offset_within_region;
> + msg.fds[region] = get_fd_from_hostaddr(host_addr, &offset);
Since you already have section.mr you cna use memory_region_get_fd.
> + msg.data1.sync_sysmem.offsets[region] = offset;
> + }
> + mpqemu_msg_send(&msg, sync->mpqemu_link->com);
> +}
> +
> +void deconfigure_memory_sync(RemoteMemSync *sync)
> +{
> + memory_listener_unregister(&sync->listener);
> +}
> +
> +/*
> + * TODO: Memory Sync need not be instantianted once per every proxy device.
> + * All remote devices are going to get the exact same updates at the
> + * same time. It therefore makes sense to have a broadcast model.
> + *
> + * Broadcast model would involve running the MemorySync object in a
> + * thread. MemorySync would contain a list of mpqemu-link objects
> + * that need notification. proxy_ml_commit() could send the same
> + * message to all the links at the same time.
> + */
> +void configure_memory_sync(RemoteMemSync *sync, MPQemuLinkState *mpqemu_link)
> +{
> + sync->n_mr_sections = 0;
> + sync->mr_sections = NULL;
> +
> + sync->mpqemu_link = mpqemu_link;
> +
> + sync->listener.begin = proxy_ml_begin;
> + sync->listener.commit = proxy_ml_commit;
> + sync->listener.region_add = proxy_ml_region_addnop;
> + sync->listener.region_nop = proxy_ml_region_addnop;
> + sync->listener.priority = 10;
> +
> + memory_listener_register(&sync->listener, &address_space_memory);
> +}
> diff --git a/hw/proxy/qemu-proxy.c b/hw/proxy/qemu-proxy.c
> index b17d9bb..d3a9d38 100644
> --- a/hw/proxy/qemu-proxy.c
> +++ b/hw/proxy/qemu-proxy.c
> @@ -16,6 +16,8 @@
> #include "qapi/qmp/qjson.h"
> #include "qapi/qmp/qstring.h"
> #include "hw/proxy/qemu-proxy.h"
> +#include "hw/proxy/memory-sync.h"
> +#include "qom/object.h"
>
> static void pci_proxy_dev_realize(PCIDevice *dev, Error **errp);
>
> @@ -243,6 +245,8 @@ static void init_proxy(PCIDevice *dev, char *command,
> char *exec_name,
>
> mpqemu_init_channel(pdev->mpqemu_link, &pdev->mpqemu_link->com,
> pdev->socket);
> +
> + configure_memory_sync(pdev->sync, pdev->mpqemu_link);
> }
>
> static void pci_proxy_dev_realize(PCIDevice *device, Error **errp)
> @@ -261,6 +265,7 @@ static void pci_proxy_dev_realize(PCIDevice *device,
> Error **errp)
> dev->set_proxy_sock = set_proxy_sock;
> dev->get_proxy_sock = get_proxy_sock;
> dev->init_proxy = init_proxy;
> + dev->sync = REMOTE_MEM_SYNC(object_new(TYPE_MEMORY_LISTENER));
> }
>
> static void send_bar_access_msg(PCIProxyDev *dev, MemoryRegion *mr,
> diff --git a/include/hw/proxy/memory-sync.h b/include/hw/proxy/memory-sync.h
> new file mode 100644
> index 0000000..d8329c9
> --- /dev/null
> +++ b/include/hw/proxy/memory-sync.h
> @@ -0,0 +1,37 @@
> +/*
> + * Copyright © 2018, 2020 Oracle and/or its affiliates.
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + *
> + */
> +
> +#ifndef MEMORY_SYNC_H
> +#define MEMORY_SYNC_H
> +
> +#include <sys/types.h>
> +
> +#include "qemu/osdep.h"
> +#include "qom/object.h"
> +#include "exec/memory.h"
> +#include "io/mpqemu-link.h"
> +
> +#define TYPE_MEMORY_LISTENER "memory-listener"
> +#define REMOTE_MEM_SYNC(obj) \
> + OBJECT_CHECK(RemoteMemSync, (obj), TYPE_MEMORY_LISTENER)
> +
> +typedef struct RemoteMemSync {
> + Object obj;
> +
> + MemoryListener listener;
> +
> + int n_mr_sections;
> + MemoryRegionSection *mr_sections;
> +
> + MPQemuLinkState *mpqemu_link;
> +} RemoteMemSync;
> +
> +void configure_memory_sync(RemoteMemSync *sync, MPQemuLinkState
> *mpqemu_link);
> +void deconfigure_memory_sync(RemoteMemSync *sync);
> +
> +#endif
> diff --git a/include/hw/proxy/qemu-proxy.h b/include/hw/proxy/qemu-proxy.h
> index 44e370e..c93ffe3 100644
> --- a/include/hw/proxy/qemu-proxy.h
> +++ b/include/hw/proxy/qemu-proxy.h
> @@ -10,6 +10,7 @@
> #define QEMU_PROXY_H
>
> #include "io/mpqemu-link.h"
> +#include "hw/proxy/memory-sync.h"
>
> #define TYPE_PCI_PROXY_DEV "pci-proxy-dev"
>
> @@ -37,8 +38,12 @@ extern const MemoryRegionOps proxy_default_ops;
> struct PCIProxyDev {
> PCIDevice parent_dev;
>
> + int n_mr_sections;
> + MemoryRegionSection *mr_sections;
> +
> MPQemuLinkState *mpqemu_link;
>
> + RemoteMemSync *sync;
> pid_t remote_pid;
> int socket;
>
> diff --git a/remote/remote-main.c b/remote/remote-main.c
> index acd8daf..9512a3b 100644
> --- a/remote/remote-main.c
> +++ b/remote/remote-main.c
> @@ -34,6 +34,7 @@
> #include "block/block.h"
> #include "exec/ramlist.h"
> #include "exec/memattrs.h"
> +#include "exec/address-spaces.h"
>
> static MPQemuLinkState *mpqemu_link;
> PCIDevice *remote_pci_dev;
> @@ -161,6 +162,16 @@ static void process_msg(GIOCondition cond, MPQemuChannel
> *chan)
> goto finalize_loop;
> }
> break;
> + case SYNC_SYSMEM:
> + /*
> + * TODO: ensure no active DMA is happening when
> + * sysmem is being updated
In practice this turns out to be hard!
Dave
> + */
> + remote_sysmem_reconfig(msg, &err);
> + if (err) {
> + goto finalize_loop;
> + }
> + break;
> default:
> error_setg(&err, "Unknown command");
> goto finalize_loop;
> --
> 1.8.3.1
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
