From 8d3bc0b75318dce70928b8bde1a49e632adf5137 Mon Sep 17 00:00:00 2001 From: Roman Kagan Date: Fri, 21 Sep 2018 11:22:15 +0300 Subject: hyperv: add support for KVM_HYPERV_EVENTFD When setting up a notifier for Hyper-V event connection, try to use the KVM-assisted one first, and fall back to userspace handling of the hypercall if the kernel doesn't provide the requested feature. Signed-off-by: Roman Kagan Message-Id: <20180921082217.29481-9-rkagan@virtuozzo.com> Signed-off-by: Paolo Bonzini --- hw/hyperv/hyperv.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) (limited to 'hw/hyperv') diff --git a/hw/hyperv/hyperv.c b/hw/hyperv/hyperv.c index d745016..7a1c1bb 100644 --- a/hw/hyperv/hyperv.c +++ b/hw/hyperv/hyperv.c @@ -13,6 +13,7 @@ #include "exec/address-spaces.h" #include "sysemu/kvm.h" #include "qemu/bitops.h" +#include "qemu/error-report.h" #include "qemu/queue.h" #include "qemu/rcu.h" #include "qemu/rcu_queue.h" @@ -470,7 +471,7 @@ static void __attribute__((constructor)) hv_init(void) qemu_mutex_init(&handlers_mutex); } -int hyperv_set_event_flag_handler(uint32_t conn_id, EventNotifier *notifier) +static int set_event_flag_handler(uint32_t conn_id, EventNotifier *notifier) { int ret; EventFlagHandler *handler; @@ -503,6 +504,30 @@ unlock: return ret; } +static bool process_event_flags_userspace; + +int hyperv_set_event_flag_handler(uint32_t conn_id, EventNotifier *notifier) +{ + if (!process_event_flags_userspace && + !kvm_check_extension(kvm_state, KVM_CAP_HYPERV_EVENTFD)) { + process_event_flags_userspace = true; + + warn_report("Hyper-V event signaling is not supported by this kernel; " + "using slower userspace hypercall processing"); + } + + if (!process_event_flags_userspace) { + struct kvm_hyperv_eventfd hvevfd = { + .conn_id = conn_id, + .fd = notifier ? event_notifier_get_fd(notifier) : -1, + .flags = notifier ? 0 : KVM_HYPERV_EVENTFD_DEASSIGN, + }; + + return kvm_vm_ioctl(kvm_state, KVM_HYPERV_EVENTFD, &hvevfd); + } + return set_event_flag_handler(conn_id, notifier); +} + uint16_t hyperv_hcall_signal_event(uint64_t param, bool fast) { uint16_t ret; -- cgit v1.1