On Tue, Jun 12, 2012 at 03:01:23PM +0300, Gleb Natapov wrote: > Current code assumes that IO exit was due to instruction emulation > and handles execution back to emulator directly. This patch adds new > userspace IO exit completion callback that can be set by any other code > that caused IO exit to userspace. > > Signed-off-by: Gleb Natapov <[email protected]> > --- > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/x86.c | 92 > +++++++++++++++++++++++---------------- > 2 files changed, 56 insertions(+), 37 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index db7c1f2..1a1bba6 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -406,6 +406,7 @@ struct kvm_vcpu_arch { > struct x86_emulate_ctxt emulate_ctxt; > bool emulate_regs_need_sync_to_vcpu; > bool emulate_regs_need_sync_from_vcpu; > + int (*complete_userspace_io)(struct kvm_vcpu *vcpu); > > gpa_t time; > struct pvclock_vcpu_time_info hv_clock; > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index a01a424..6fa0e21 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4547,6 +4547,9 @@ static bool retry_instruction(struct x86_emulate_ctxt > *ctxt, > return true; > } > > +static int complete_emulated_mmio(struct kvm_vcpu *vcpu); > +static int complete_emulated_pio(struct kvm_vcpu *vcpu); > + > int x86_emulate_instruction(struct kvm_vcpu *vcpu, > unsigned long cr2, > int emulation_type, > @@ -4617,13 +4620,16 @@ restart: > } else if (vcpu->arch.pio.count) { > if (!vcpu->arch.pio.in) > vcpu->arch.pio.count = 0; > - else > + else { > writeback = false; > + vcpu->arch.complete_userspace_io = > complete_emulated_pio; > + } > r = EMULATE_DO_MMIO; > } else if (vcpu->mmio_needed) { > if (!vcpu->mmio_is_write) > writeback = false; > r = EMULATE_DO_MMIO; > + vcpu->arch.complete_userspace_io = complete_emulated_mmio; > } else if (r == EMULATION_RESTART) > goto restart; > else > @@ -5474,6 +5480,24 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) > return r; > } > > +static inline int complete_emulated_io(struct kvm_vcpu *vcpu) > +{ > + int r; > + vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); > + r = emulate_instruction(vcpu, EMULTYPE_NO_DECODE); > + srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); > + if (r != EMULATE_DONE) > + return 0; > + return 1; > +} > + > +static int complete_emulated_pio(struct kvm_vcpu *vcpu) > +{ > + BUG_ON(!vcpu->arch.pio.count); > + > + return complete_emulated_io(vcpu); > +} > + > /* > * Implements the following, as a state machine: > * > @@ -5490,47 +5514,37 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) > * copy data > * exit > */ > -static int complete_mmio(struct kvm_vcpu *vcpu) > +static int complete_emulated_mmio(struct kvm_vcpu *vcpu) > { > struct kvm_run *run = vcpu->run; > struct kvm_mmio_fragment *frag; > - int r; > > - if (!(vcpu->arch.pio.count || vcpu->mmio_needed)) > - return 1; > + BUG_ON(!vcpu->mmio_needed); > > - if (vcpu->mmio_needed) { > - /* Complete previous fragment */ > - frag = &vcpu->mmio_fragments[vcpu->mmio_cur_fragment++]; > - if (!vcpu->mmio_is_write) > - memcpy(frag->data, run->mmio.data, frag->len); > - if (vcpu->mmio_cur_fragment == vcpu->mmio_nr_fragments) { > - vcpu->mmio_needed = 0; > - if (vcpu->mmio_is_write) > - return 1; > - vcpu->mmio_read_completed = 1; > - goto done; > - } > - /* Initiate next fragment */ > - ++frag; > - run->exit_reason = KVM_EXIT_MMIO; > - run->mmio.phys_addr = frag->gpa; > + /* Complete previous fragment */ > + frag = &vcpu->mmio_fragments[vcpu->mmio_cur_fragment++]; > + if (!vcpu->mmio_is_write) > + memcpy(frag->data, run->mmio.data, frag->len); > + if (vcpu->mmio_cur_fragment == vcpu->mmio_nr_fragments) { > + vcpu->mmio_needed = 0; > if (vcpu->mmio_is_write) > - memcpy(run->mmio.data, frag->data, frag->len); > - run->mmio.len = frag->len; > - run->mmio.is_write = vcpu->mmio_is_write; > - return 0; > - > - } > -done: > - vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); > - r = emulate_instruction(vcpu, EMULTYPE_NO_DECODE); > - srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); > - if (r != EMULATE_DONE) > - return 0; > - return 1; > + return 1; > + vcpu->mmio_read_completed = 1; > + return complete_emulated_io(vcpu); > + } > + /* Initiate next fragment */ > + ++frag; > + run->exit_reason = KVM_EXIT_MMIO; > + run->mmio.phys_addr = frag->gpa; > + if (vcpu->mmio_is_write) > + memcpy(run->mmio.data, frag->data, frag->len); > + run->mmio.len = frag->len; > + run->mmio.is_write = vcpu->mmio_is_write; > + vcpu->arch.complete_userspace_io = complete_emulated_mmio; > + return 0; > } > > + > int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) > { > int r; > @@ -5557,9 +5571,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, > struct kvm_run *kvm_run) > } > } > > - r = complete_mmio(vcpu); > - if (r <= 0) > - goto out; > + if (unlikely(vcpu->arch.complete_userspace_io)) { > + int (*cui)(struct kvm_vcpu *) = > vcpu->arch.complete_userspace_io; > + vcpu->arch.complete_userspace_io = NULL; > + r = cui(vcpu); > + if (r <= 0)
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