On Mon, 16 Sep 2024, Edgar E. Iglesias wrote:
> From: "Edgar E. Iglesias" <edgar.igles...@amd.com>
>
> Expose handle_bufioreq in xen_register_ioreq().
> This is to allow machines to enable or disable buffered ioreqs.
>
> No functional change since all callers still set it to
> HVM_IOREQSRV_BUFIOREQ_ATOMIC.
>
> Signed-off-by: Edgar E. Iglesias <edgar.igles...@amd.com>
> ---
> hw/i386/xen/xen-hvm.c | 4 +-
> hw/xen/xen-hvm-common.c | 100 +++++++++++++++++++-------------
> hw/xen/xen-pvh-common.c | 4 +-
> include/hw/xen/xen-hvm-common.h | 3 +
> include/hw/xen/xen_native.h | 3 +-
> 5 files changed, 70 insertions(+), 44 deletions(-)
>
> diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
> index 4f6446600c..d3df488c48 100644
> --- a/hw/i386/xen/xen-hvm.c
> +++ b/hw/i386/xen/xen-hvm.c
> @@ -614,7 +614,9 @@ void xen_hvm_init_pc(PCMachineState *pcms, MemoryRegion
> **ram_memory)
>
> state = g_new0(XenIOState, 1);
>
> - xen_register_ioreq(state, max_cpus, &xen_memory_listener);
> + xen_register_ioreq(state, max_cpus,
> + HVM_IOREQSRV_BUFIOREQ_ATOMIC,
> + &xen_memory_listener);
>
> xen_is_stubdomain = xen_check_stubdomain(state->xenstore);
>
> diff --git a/hw/xen/xen-hvm-common.c b/hw/xen/xen-hvm-common.c
> index 3a9d6f981b..d8824cccf1 100644
> --- a/hw/xen/xen-hvm-common.c
> +++ b/hw/xen/xen-hvm-common.c
> @@ -667,6 +667,8 @@ static int xen_map_ioreq_server(XenIOState *state)
> xen_pfn_t ioreq_pfn;
> xen_pfn_t bufioreq_pfn;
> evtchn_port_t bufioreq_evtchn;
> + unsigned long num_frames = 1;
> + unsigned long frame = 1;
> int rc;
>
> /*
> @@ -675,59 +677,72 @@ static int xen_map_ioreq_server(XenIOState *state)
> */
> QEMU_BUILD_BUG_ON(XENMEM_resource_ioreq_server_frame_bufioreq != 0);
> QEMU_BUILD_BUG_ON(XENMEM_resource_ioreq_server_frame_ioreq(0) != 1);
> +
> + if (state->has_bufioreq) {
> + frame = 0;
> + num_frames = 2;
> + }
> state->fres = xenforeignmemory_map_resource(xen_fmem, xen_domid,
> XENMEM_resource_ioreq_server,
> - state->ioservid, 0, 2,
> + state->ioservid,
> + frame, num_frames,
> &addr,
> PROT_READ | PROT_WRITE, 0);
> if (state->fres != NULL) {
> trace_xen_map_resource_ioreq(state->ioservid, addr);
> - state->buffered_io_page = addr;
> - state->shared_page = addr + XC_PAGE_SIZE;
> + state->shared_page = addr;
> + if (state->has_bufioreq) {
> + state->buffered_io_page = addr;
> + state->shared_page = addr + XC_PAGE_SIZE;
> + }
> } else if (errno != EOPNOTSUPP) {
> error_report("failed to map ioreq server resources: error %d
> handle=%p",
> errno, xen_xc);
> return -1;
> }
>
> - rc = xen_get_ioreq_server_info(xen_domid, state->ioservid,
> - (state->shared_page == NULL) ?
> - &ioreq_pfn : NULL,
> - (state->buffered_io_page == NULL) ?
> - &bufioreq_pfn : NULL,
> - &bufioreq_evtchn);
> - if (rc < 0) {
> - error_report("failed to get ioreq server info: error %d handle=%p",
> - errno, xen_xc);
> - return rc;
> - }
> -
> - if (state->shared_page == NULL) {
> - trace_xen_map_ioreq_server_shared_page(ioreq_pfn);
> + if (state->has_bufioreq) {
> + rc = xen_get_ioreq_server_info(xen_domid, state->ioservid,
> + (state->shared_page == NULL) ?
> + &ioreq_pfn : NULL,
> + (state->buffered_io_page == NULL) ?
> + &bufioreq_pfn : NULL,
> + &bufioreq_evtchn);
> + if (rc < 0) {
> + error_report("failed to get ioreq server info: error %d
> handle=%p",
> + errno, xen_xc);
> + return rc;
> + }
>
> - state->shared_page = xenforeignmemory_map(xen_fmem, xen_domid,
> - PROT_READ | PROT_WRITE,
> - 1, &ioreq_pfn, NULL);
> if (state->shared_page == NULL) {
> - error_report("map shared IO page returned error %d handle=%p",
> - errno, xen_xc);
> + trace_xen_map_ioreq_server_shared_page(ioreq_pfn);
> +
> + state->shared_page = xenforeignmemory_map(xen_fmem, xen_domid,
> + PROT_READ | PROT_WRITE,
> + 1, &ioreq_pfn, NULL);
> + if (state->shared_page == NULL) {
> + error_report("map shared IO page returned error %d
> handle=%p",
> + errno, xen_xc);
> + }
> }
> - }
If I am reading the code right the calls to xen_get_ioreq_server_info
and xenforeignmemory_map were not done to setup bufioreq. They were done
for legacy compatibility to support systems where
xenforeignmemory_map_resource returns EOPNOTSUPP.
I think we should either get rid of this legacy path completely, or
keep it for both bufioreq and non-bufioreq.
> - if (state->buffered_io_page == NULL) {
> - trace_xen_map_ioreq_server_buffered_io_page(bufioreq_pfn);
> -
> - state->buffered_io_page = xenforeignmemory_map(xen_fmem, xen_domid,
> - PROT_READ |
> PROT_WRITE,
> - 1, &bufioreq_pfn,
> - NULL);
> if (state->buffered_io_page == NULL) {
> - error_report("map buffered IO page returned error %d", errno);
> - return -1;
> + trace_xen_map_ioreq_server_buffered_io_page(bufioreq_pfn);
> +
> + state->buffered_io_page = xenforeignmemory_map(xen_fmem,
> xen_domid,
> + PROT_READ | PROT_WRITE,
> + 1, &bufioreq_pfn,
> + NULL);
> + if (state->buffered_io_page == NULL) {
> + error_report("map buffered IO page returned error %d",
> errno);
> + return -1;
> + }
> }
> }
>
> - if (state->shared_page == NULL || state->buffered_io_page == NULL) {
> +
> + if (state->shared_page == NULL ||
> + (state->has_bufioreq && state->buffered_io_page == NULL)) {
> return -1;
> }
>
> @@ -830,14 +845,15 @@ static void xen_do_ioreq_register(XenIOState *state,
> state->ioreq_local_port[i] = rc;
> }
>
> - rc = qemu_xen_evtchn_bind_interdomain(state->xce_handle, xen_domid,
> - state->bufioreq_remote_port);
> - if (rc == -1) {
> - error_report("buffered evtchn bind error %d", errno);
> - goto err;
> + if (state->has_bufioreq) {
> + rc = qemu_xen_evtchn_bind_interdomain(state->xce_handle, xen_domid,
> + state->bufioreq_remote_port);
> + if (rc == -1) {
> + error_report("buffered evtchn bind error %d", errno);
> + goto err;
> + }
> + state->bufioreq_local_port = rc;
> }
> - state->bufioreq_local_port = rc;
> -
> /* Init RAM management */
> #ifdef XEN_COMPAT_PHYSMAP
> xen_map_cache_init(xen_phys_offset_to_gaddr, state);
> @@ -865,6 +881,7 @@ err:
> }
>
> void xen_register_ioreq(XenIOState *state, unsigned int max_cpus,
> + int handle_bufioreq,
> const MemoryListener *xen_memory_listener)
> {
> int rc;
> @@ -883,7 +900,8 @@ void xen_register_ioreq(XenIOState *state, unsigned int
> max_cpus,
> goto err;
> }
>
> - rc = xen_create_ioreq_server(xen_domid, &state->ioservid);
> + state->has_bufioreq = handle_bufioreq != HVM_IOREQSRV_BUFIOREQ_OFF;
> + rc = xen_create_ioreq_server(xen_domid, handle_bufioreq,
> &state->ioservid);
> if (!rc) {
> xen_do_ioreq_register(state, max_cpus, xen_memory_listener);
> } else {
> diff --git a/hw/xen/xen-pvh-common.c b/hw/xen/xen-pvh-common.c
> index 28d7168446..08641fdcec 100644
> --- a/hw/xen/xen-pvh-common.c
> +++ b/hw/xen/xen-pvh-common.c
> @@ -194,7 +194,9 @@ static void xen_pvh_init(MachineState *ms)
> }
>
> xen_pvh_init_ram(s, sysmem);
> - xen_register_ioreq(&s->ioreq, ms->smp.max_cpus, &xen_memory_listener);
> + xen_register_ioreq(&s->ioreq, ms->smp.max_cpus,
> + HVM_IOREQSRV_BUFIOREQ_ATOMIC,
> + &xen_memory_listener);
>
> if (s->cfg.virtio_mmio_num) {
> xen_create_virtio_mmio_devices(s);
> diff --git a/include/hw/xen/xen-hvm-common.h b/include/hw/xen/xen-hvm-common.h
> index 3d796235dc..7246941fe5 100644
> --- a/include/hw/xen/xen-hvm-common.h
> +++ b/include/hw/xen/xen-hvm-common.h
> @@ -81,6 +81,8 @@ typedef struct XenIOState {
> QLIST_HEAD(, XenPciDevice) dev_list;
> DeviceListener device_listener;
>
> + bool has_bufioreq;
> +
> Notifier exit;
> } XenIOState;
>
> @@ -95,6 +97,7 @@ void xen_device_unrealize(DeviceListener *listener,
> DeviceState *dev);
>
> void xen_hvm_change_state_handler(void *opaque, bool running, RunState
> rstate);
> void xen_register_ioreq(XenIOState *state, unsigned int max_cpus,
> + int handle_bufioreq,
> const MemoryListener *xen_memory_listener);
>
> void cpu_ioreq_pio(ioreq_t *req);
> diff --git a/include/hw/xen/xen_native.h b/include/hw/xen/xen_native.h
> index 1a5ad693a4..5caf91a616 100644
> --- a/include/hw/xen/xen_native.h
> +++ b/include/hw/xen/xen_native.h
> @@ -464,10 +464,11 @@ static inline void xen_unmap_pcidev(domid_t dom,
> }
>
> static inline int xen_create_ioreq_server(domid_t dom,
> + int handle_bufioreq,
> ioservid_t *ioservid)
> {
> int rc = xendevicemodel_create_ioreq_server(xen_dmod, dom,
> - HVM_IOREQSRV_BUFIOREQ_ATOMIC,
> + handle_bufioreq,
> ioservid);
>
> if (rc == 0) {
> --
> 2.43.0
>
