From 765eaa0f70eaa274ec8b815d8c210c20cf7b6dbc Mon Sep 17 00:00:00 2001 From: Andrey Smetanin Date: Mon, 30 Nov 2015 19:22:20 +0300 Subject: [PATCH] kvm/x86: Hyper-V SynIC message slot pending clearing at SINT ack The SynIC message protocol mandates that the message slot is claimed by atomically setting message type to something other than HVMSG_NONE. If another message is to be delivered while the slot is still busy, message pending flag is asserted to indicate to the guest that the hypervisor wants to be notified when the slot is released. To make sure the protocol works regardless of where the message sources are (kernel or userspace), clear the pending flag on SINT ACK notification, and let the message sources compete for the slot again. Signed-off-by: Andrey Smetanin Reviewed-by: Roman Kagan CC: Gleb Natapov CC: Paolo Bonzini CC: "K. Y. Srinivasan" CC: Haiyang Zhang CC: Vitaly Kuznetsov CC: Roman Kagan CC: Denis V. Lunev CC: qemu-devel@nongnu.org Signed-off-by: Paolo Bonzini --- arch/x86/kvm/hyperv.c | 31 +++++++++++++++++++++++++++++++ include/linux/kvm_host.h | 2 ++ 2 files changed, 33 insertions(+) diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 99589268fe5d..6412b6b504b5 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -27,6 +27,7 @@ #include "hyperv.h" #include +#include #include #include @@ -116,13 +117,43 @@ static struct kvm_vcpu_hv_synic *synic_get(struct kvm *kvm, u32 vcpu_id) return (synic->active) ? synic : NULL; } +static void synic_clear_sint_msg_pending(struct kvm_vcpu_hv_synic *synic, + u32 sint) +{ + struct kvm_vcpu *vcpu = synic_to_vcpu(synic); + struct page *page; + gpa_t gpa; + struct hv_message *msg; + struct hv_message_page *msg_page; + + gpa = synic->msg_page & PAGE_MASK; + page = kvm_vcpu_gfn_to_page(vcpu, gpa >> PAGE_SHIFT); + if (is_error_page(page)) { + vcpu_err(vcpu, "Hyper-V SynIC can't get msg page, gpa 0x%llx\n", + gpa); + return; + } + msg_page = kmap_atomic(page); + + msg = &msg_page->sint_message[sint]; + msg->header.message_flags.msg_pending = 0; + + kunmap_atomic(msg_page); + kvm_release_page_dirty(page); + kvm_vcpu_mark_page_dirty(vcpu, gpa >> PAGE_SHIFT); +} + static void kvm_hv_notify_acked_sint(struct kvm_vcpu *vcpu, u32 sint) { struct kvm *kvm = vcpu->kvm; + struct kvm_vcpu_hv_synic *synic = vcpu_to_synic(vcpu); int gsi, idx; vcpu_debug(vcpu, "Hyper-V SynIC acked sint %d\n", sint); + if (synic->msg_page & HV_SYNIC_SIMP_ENABLE) + synic_clear_sint_msg_pending(synic, sint); + idx = srcu_read_lock(&kvm->irq_srcu); gsi = atomic_read(&vcpu_to_synic(vcpu)->sint_to_gsi[sint]); if (gsi != -1) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 590c46e672df..f44c24b81b17 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -450,6 +450,8 @@ struct kvm { #define vcpu_debug(vcpu, fmt, ...) \ kvm_debug("vcpu%i " fmt, (vcpu)->vcpu_id, ## __VA_ARGS__) +#define vcpu_err(vcpu, fmt, ...) \ + kvm_err("vcpu%i " fmt, (vcpu)->vcpu_id, ## __VA_ARGS__) static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i) { -- 2.20.1