From a77eb86f44e52c5aea7f0ba7023600c043a9cdcd Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Mon, 14 Oct 2013 10:25:39 +0200 Subject: libxl,xl: add max_event_channels option to xl configuration file Add the 'max_event_channels' option to the xl configuration file to limit the number of event channels that domain may use. Plumb this option through to libxl via a new libxl_build_info field and call xc_domain_set_max_evtchn() in the post build stage of domain creation. A new LIBXL_HAVE_BUILDINFO_EVENT_CHANNELS #define indicates that this new field is available. The default value of 1023 limits the domain to using the minimum amount of global mapping pages and at most 5 xenheap pages. Signed-off-by: David Vrabel Acked-by: Ian Campbell Acked-by: Keir Fraser --- docs/man/xl.cfg.pod.5 | 11 +++++++++++ tools/libxl/libxl.h | 5 +++++ tools/libxl/libxl_create.c | 3 +++ tools/libxl/libxl_dom.c | 7 +++++++ tools/libxl/libxl_types.idl | 1 + tools/libxl/xl_cmdimpl.c | 3 +++ 6 files changed, 30 insertions(+) diff --git a/docs/man/xl.cfg.pod.5 b/docs/man/xl.cfg.pod.5 index cd9696934b..278dba10d8 100644 --- a/docs/man/xl.cfg.pod.5 +++ b/docs/man/xl.cfg.pod.5 @@ -580,6 +580,17 @@ Allow a guest to access specific physical IRQs. It is recommended to use this option only for trusted VMs under administrator control. +=item B + +Limit the guest to using at most N event channels (PV interrupts). +Guests use hypervisor resources for each event channel they use. + +The default of 1023 should be sufficient for typical guests. The +maximum value depends what the guest supports. Guests supporting the +FIFO-based event channel ABI support up to 131,071 event channels. +Other guests are limited to 4095 (64-bit x86 and ARM) or 1023 (32-bit +x86). + =back =head2 Paravirtualised (PV) Guest Specific Options diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h index c9d9535b32..1c6675d0da 100644 --- a/tools/libxl/libxl.h +++ b/tools/libxl/libxl.h @@ -89,6 +89,11 @@ */ #define LIBXL_HAVE_BUILDINFO_HVM_VENDOR_DEVICE 1 +/* + * The libxl_domain_build_info has the event_channels field. + */ +#define LIBXL_HAVE_BUILDINFO_EVENT_CHANNELS 1 + /* * libxl ABI compatibility * diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c index c5ec577127..1b320d3c92 100644 --- a/tools/libxl/libxl_create.c +++ b/tools/libxl/libxl_create.c @@ -208,6 +208,9 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc, libxl_defbool_setdefault(&b_info->disable_migrate, false); + if (!b_info->event_channels) + b_info->event_channels = 1023; + switch (b_info->type) { case LIBXL_DOMAIN_TYPE_HVM: if (b_info->shadow_memkb == LIBXL_MEMKB_DEFAULT) diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c index 6e2252afbe..356f920a6d 100644 --- a/tools/libxl/libxl_dom.c +++ b/tools/libxl/libxl_dom.c @@ -268,6 +268,13 @@ int libxl__build_post(libxl__gc *gc, uint32_t domid, if (rc) return rc; + rc = xc_domain_set_max_evtchn(ctx->xch, domid, info->event_channels); + if (rc) { + LOG(ERROR, "Failed to set event channel limit to %d (%d)", + info->event_channels, rc); + return ERROR_FAIL; + } + libxl_cpuid_apply_policy(ctx, domid); if (info->cpuid != NULL) libxl_cpuid_set(ctx, domid, info->cpuid); diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl index b5d0b70064..d2cea8a971 100644 --- a/tools/libxl/libxl_types.idl +++ b/tools/libxl/libxl_types.idl @@ -312,6 +312,7 @@ libxl_domain_build_info = Struct("domain_build_info",[ ("irqs", Array(uint32, "num_irqs")), ("iomem", Array(libxl_iomem_range, "num_iomem")), ("claim_mode", libxl_defbool), + ("event_channels", uint32), ("u", KeyedUnion(None, libxl_domain_type, "type", [("hvm", Struct(None, [("firmware", string), ("bios", libxl_bios_type), diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c index 14bb385f1a..a8261be048 100644 --- a/tools/libxl/xl_cmdimpl.c +++ b/tools/libxl/xl_cmdimpl.c @@ -845,6 +845,9 @@ static void parse_config_data(const char *config_source, if (!xlu_cfg_get_long (config, "videoram", &l, 0)) b_info->video_memkb = l * 1024; + if (!xlu_cfg_get_long(config, "max_event_channels", &l, 0)) + b_info->event_channels = l; + switch(b_info->type) { case LIBXL_DOMAIN_TYPE_HVM: if (!xlu_cfg_get_string (config, "kernel", &buf, 0)) -- cgit v1.2.3