KVM: SVM: Implement GIF, clgi and stgi

This patch implements the GIF flag and the clgi and stgi instructions that
set this flag. Only if the flag is set (default), interrupts can be received by
the CPU.

To keep the information about that somewhere, this patch adds a new hidden
flags vector. that is used to store information that does not go into the
vmcb, but is SVM specific.

I tried to write some code to make -no-kvm-irqchip work too, but the first
level guest won't even boot with that atm, so I ditched it.

v2 moves the hflags to x86 generic code
v3 makes use of the new permission helper
v6 only enables interrupt_window if GIF=1

Acked-by: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 55764eca43b609d765f4baaf9e792e2301ce7a50..134e79fbca29a150429e560b71d714e21c263255 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -259,6 +259,7 @@ struct kvm_vcpu_arch {
        unsigned long cr3;
        unsigned long cr4;
        unsigned long cr8;
+       u32 hflags;
        u64 pdptrs[4]; /* pae */
        u64 shadow_efer;
        u64 apic_base;
@@ -738,6 +739,8 @@ enum {
        TASK_SWITCH_GATE = 3,
 };
 
+#define HF_GIF_MASK            (1 << 0)
+
 /*
  * Hardware virtualization extension instructions may fault if a
  * reboot turns off virtualization while processes are running.

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 2e6661c4a2d2f47de88b8ed93b496794d96ed8e2..ae30c58865771e3c68371565c28ff97f2618518c 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -251,7 +251,7 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
        kvm_rip_write(vcpu, svm->next_rip);
        svm->vmcb->control.int_state &= ~SVM_INTERRUPT_SHADOW_MASK;
 
-       vcpu->arch.interrupt_window_open = 1;
+       vcpu->arch.interrupt_window_open = (svm->vcpu.arch.hflags & HF_GIF_MASK);
 }
 
 static int has_svm(void)
@@ -600,6 +600,8 @@ static void init_vmcb(struct vcpu_svm *svm)
                save->cr4 = 0;
        }
        force_new_asid(&svm->vcpu);
+
+       svm->vcpu.arch.hflags = HF_GIF_MASK;
 }
 
 static int svm_vcpu_reset(struct kvm_vcpu *vcpu)
@@ -1234,6 +1236,36 @@ static int nested_svm_do(struct vcpu_svm *svm,
        return retval;
 }
 
+static int stgi_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
+{
+       if (nested_svm_check_permissions(svm))
+               return 1;
+
+       svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
+       skip_emulated_instruction(&svm->vcpu);
+
+       svm->vcpu.arch.hflags |= HF_GIF_MASK;
+
+       return 1;
+}
+
+static int clgi_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
+{
+       if (nested_svm_check_permissions(svm))
+               return 1;
+
+       svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
+       skip_emulated_instruction(&svm->vcpu);
+
+       svm->vcpu.arch.hflags &= ~HF_GIF_MASK;
+
+       /* After a CLGI no interrupts should come */
+       svm_clear_vintr(svm);
+       svm->vmcb->control.int_ctl &= ~V_IRQ_MASK;
+
+       return 1;
+}
+
 static int invalid_op_interception(struct vcpu_svm *svm,
                                   struct kvm_run *kvm_run)
 {
@@ -1535,8 +1567,8 @@ static int (*svm_exit_handlers[])(struct vcpu_svm *svm,
        [SVM_EXIT_VMMCALL]                      = vmmcall_interception,
        [SVM_EXIT_VMLOAD]                       = invalid_op_interception,
        [SVM_EXIT_VMSAVE]                       = invalid_op_interception,
-       [SVM_EXIT_STGI]                         = invalid_op_interception,
-       [SVM_EXIT_CLGI]                         = invalid_op_interception,
+       [SVM_EXIT_STGI]                         = stgi_interception,
+       [SVM_EXIT_CLGI]                         = clgi_interception,
        [SVM_EXIT_SKINIT]                       = invalid_op_interception,
        [SVM_EXIT_WBINVD]                       = emulate_on_interception,
        [SVM_EXIT_MONITOR]                      = invalid_op_interception,
@@ -1684,6 +1716,9 @@ static void svm_intr_assist(struct kvm_vcpu *vcpu)
        if (!kvm_cpu_has_interrupt(vcpu))
                goto out;
 
+       if (!(svm->vcpu.arch.hflags & HF_GIF_MASK))
+               goto out;
+
        if (!(vmcb->save.rflags & X86_EFLAGS_IF) ||
            (vmcb->control.int_state & SVM_INTERRUPT_SHADOW_MASK) ||
            (vmcb->control.event_inj & SVM_EVTINJ_VALID)) {
@@ -1711,7 +1746,8 @@ static void kvm_reput_irq(struct vcpu_svm *svm)
        }
 
        svm->vcpu.arch.interrupt_window_open =
-               !(control->int_state & SVM_INTERRUPT_SHADOW_MASK);
+               !(control->int_state & SVM_INTERRUPT_SHADOW_MASK) &&
+                (svm->vcpu.arch.hflags & HF_GIF_MASK);
 }
 
 static void svm_do_inject_vector(struct vcpu_svm *svm)
@@ -1735,7 +1771,8 @@ static void do_interrupt_requests(struct kvm_vcpu *vcpu,
 
        svm->vcpu.arch.interrupt_window_open =
                (!(control->int_state & SVM_INTERRUPT_SHADOW_MASK) &&
-                (svm->vmcb->save.rflags & X86_EFLAGS_IF));
+                (svm->vmcb->save.rflags & X86_EFLAGS_IF) &&
+                (svm->vcpu.arch.hflags & HF_GIF_MASK));
 
        if (svm->vcpu.arch.interrupt_window_open && svm->vcpu.arch.irq_summary)
                /*