On 22/10/2015 18:10, Andrey Smetanin wrote:
> A new vcpu exit is introduced to notify the userspace of the
> changes in Hyper-V SynIC configuration triggered by guest writing to the
> corresponding MSRs.
>
> Changes v3:
> * added KVM_EXIT_HYPERV types and structs notes into docs
>
> Signed-off-by: Andrey Smetanin <asmetanin@xxxxxxxxxxxxx>
> Reviewed-by: Roman Kagan <rkagan@xxxxxxxxxxxxx>
> Signed-off-by: Denis V. Lunev <den@xxxxxxxxxx>
> CC: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> CC: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
> CC: Gleb Natapov <gleb@xxxxxxxxxx>
> CC: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> CC: Roman Kagan <rkagan@xxxxxxxxxxxxx>
>
> ---
> Documentation/virtual/kvm/api.txt | 22 ++++++++++++++++++++++
> arch/x86/include/asm/kvm_host.h | 1 +
> arch/x86/kvm/hyperv.c | 17 +++++++++++++++++
> arch/x86/kvm/x86.c | 6 ++++++
> include/linux/kvm_host.h | 1 +
> include/uapi/linux/kvm.h | 17 +++++++++++++++++
> 6 files changed, 64 insertions(+)
>
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index 8710418..a6858eb 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -3337,6 +3337,28 @@ the userspace IOAPIC should process the EOI and retrigger the interrupt if
> it is still asserted. Vector is the LAPIC interrupt vector for which the
> EOI was received.
>
> + struct kvm_hyperv_exit {
> +#define KVM_EXIT_HYPERV_SYNIC 1
> + __u32 type;
> + union {
> + struct {
> + __u32 msr;
> + __u64 control;
> + __u64 evt_page;
> + __u64 msg_page;
> + } synic;
> + } u;
> + };
> + /* KVM_EXIT_HYPERV */
> + struct kvm_hyperv_exit hyperv;
> +Indicates that the VCPU exits into userspace to process some tasks
> +related to Hyper-V emulation.
> +Valid values for 'type' are:
> + KVM_EXIT_HYPERV_SYNIC -- synchronously notify user-space about
> +Hyper-V SynIC state change. Notification is used to remap SynIC
> +event/message pages and to enable/disable SynIC messages/events processing
> +in userspace.
> +
> /* Fix the size of the union. */
> char padding[256];
> };
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 8434f88..54c90d3 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -392,6 +392,7 @@ struct kvm_vcpu_hv {
> u64 hv_vapic;
> s64 runtime_offset;
> struct kvm_vcpu_hv_synic synic;
> + struct kvm_hyperv_exit exit;
> };
>
> struct kvm_vcpu_arch {
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index 8ff71f3..9443920 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -129,6 +129,20 @@ static void kvm_hv_notify_acked_sint(struct kvm_vcpu *vcpu, u32 sint)
> srcu_read_unlock(&kvm->irq_srcu, idx);
> }
>
> +static void synic_exit(struct kvm_vcpu_hv_synic *synic, u32 msr)
> +{
> + struct kvm_vcpu *vcpu = synic_to_vcpu(synic);
> + struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;
> +
> + hv_vcpu->exit.type = KVM_EXIT_HYPERV_SYNIC;
> + hv_vcpu->exit.u.synic.msr = msr;
> + hv_vcpu->exit.u.synic.control = synic->control;
> + hv_vcpu->exit.u.synic.evt_page = synic->evt_page;
> + hv_vcpu->exit.u.synic.msg_page = synic->msg_page;
> +
> + kvm_make_request(KVM_REQ_HV_EXIT, vcpu);
> +}
> +
> static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
> u32 msr, u64 data, bool host)
> {
> @@ -141,6 +155,7 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
> switch (msr) {
> case HV_X64_MSR_SCONTROL:
> synic->control = data;
> + synic_exit(synic, msr);
Another note. I am getting:
EAX=00000000 EBX=00000000 ECX=00000000 EDX=00000663
ESI=00000000 EDI=00000000 EBP=00000000 ESP=00000000
EIP=0000fff0 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 00000000 0000ffff 00009300
CS =f000 ffff0000 0000ffff 00009b00
SS =0000 00000000 0000ffff 00009300
DS =0000 00000000 0000ffff 00009300
FS =0000 00000000 0000ffff 00009300
GS =0000 00000000 0000ffff 00009300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT= 00000000 0000ffff
IDT= 00000000 0000ffff
CR0=60000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000
DR3=0000000000000000
DR6=00000000ffff0ff0 DR7=0000000000000400
EFER=0000000000000000
Code=90 90 90 90 eb c3 90 90 90 90 90 90 00 00 00 00 56 54 46 00 <90> 90
eb ac 90 90 90 90 90 90 90 90 90 90 90 90 00 00 00 00 00 00 00 00 00 00
00 00 00 00
if I run a patched QEMU but I *do not* enable the synthetic interrupt
controller. I can fix it by wrapping the calls to synic_exit with "if
(!host)", but I haven't checked yet the source---so that may not be the
proper fix. Sorry for not having looked more in detail.
Paolo
> break;
> case HV_X64_MSR_SVERSION:
> if (!host) {
> @@ -157,6 +172,7 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
> break;
> }
> synic->evt_page = data;
> + synic_exit(synic, msr);
> break;
> case HV_X64_MSR_SIMP:
> if (data & HV_SYNIC_SIMP_ENABLE)
> @@ -166,6 +182,7 @@ static int synic_set_msr(struct kvm_vcpu_hv_synic *synic,
> break;
> }
> synic->msg_page = data;
> + synic_exit(synic, msr);
> break;
> case HV_X64_MSR_EOM: {
> int i;
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index b853b2df..0704ee3 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6342,6 +6342,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> r = 0;
> goto out;
> }
> + if (kvm_check_request(KVM_REQ_HV_EXIT, vcpu)) {
> + vcpu->run->exit_reason = KVM_EXIT_HYPERV;
> + vcpu->run->hyperv = vcpu->arch.hyperv.exit;
> + r = 0;
> + goto out;
> + }
> }
>
> /*
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 43b0141..e38ac16 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -143,6 +143,7 @@ static inline bool is_error_page(struct page *page)
> #define KVM_REQ_HV_CRASH 27
> #define KVM_REQ_IOAPIC_EOI_EXIT 28
> #define KVM_REQ_HV_RESET 29
> +#define KVM_REQ_HV_EXIT 30
>
> #define KVM_USERSPACE_IRQ_SOURCE_ID 0
> #define KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID 1
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 27ce460..6e32f75 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -154,6 +154,20 @@ struct kvm_s390_skeys {
> __u32 flags;
> __u32 reserved[9];
> };
> +
> +struct kvm_hyperv_exit {
> +#define KVM_EXIT_HYPERV_SYNIC 1
> + __u32 type;
> + union {
> + struct {
> + __u32 msr;
> + __u64 control;
> + __u64 evt_page;
> + __u64 msg_page;
> + } synic;
> + } u;
> +};
> +
> #define KVM_S390_GET_SKEYS_NONE 1
> #define KVM_S390_SKEYS_MAX 1048576
>
> @@ -184,6 +198,7 @@ struct kvm_s390_skeys {
> #define KVM_EXIT_SYSTEM_EVENT 24
> #define KVM_EXIT_S390_STSI 25
> #define KVM_EXIT_IOAPIC_EOI 26
> +#define KVM_EXIT_HYPERV 27
>
> /* For KVM_EXIT_INTERNAL_ERROR */
> /* Emulate instruction failed. */
> @@ -338,6 +353,8 @@ struct kvm_run {
> struct {
> __u8 vector;
> } eoi;
> + /* KVM_EXIT_HYPERV */
> + struct kvm_hyperv_exit hyperv;
> /* Fix the size of the union. */
> char padding[256];
> };
>
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