On 12/11/2011 12:25 PM, Christoffer Dall wrote:
> From: Christoffer Dall <cd...@cs.columbia.edu>
>
> Adds a new important function in the main KVM/ARM code called
> handle_exit() which is called from kvm_arch_vcpu_ioctl_run() on returns
> from guest execution. This function examines the Hyp-Syndrome-Register
> (HSR), which contains information telling KVM what caused the exit from
> the guest.
>
> Some of the reasons for an exit are CP15 accesses, which are
> not allowed from the guest and this commits handles these exits by
commit
> emulating the intented operation in software and skip the guest
intended
> instruction.
>
> @@ -306,6 +307,62 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
> return 0;
> }
>
> +static inline int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
> + int exception_index)
> +{
> + unsigned long hsr_ec;
> +
> + if (exception_index == ARM_EXCEPTION_IRQ)
> + return 0;
> +
> + if (exception_index != ARM_EXCEPTION_HVC) {
> + kvm_err(-EINVAL, "Unsupported exception type");
> + return -EINVAL;
> + }
> +
> + hsr_ec = (vcpu->arch.hsr & HSR_EC) >> HSR_EC_SHIFT;
> + switch (hsr_ec) {
> + case HSR_EC_WFI:
> + return kvm_handle_wfi(vcpu, run);
> + case HSR_EC_CP15_32:
> + case HSR_EC_CP15_64:
> + return kvm_handle_cp15_access(vcpu, run);
> + case HSR_EC_CP14_MR:
> + return kvm_handle_cp14_access(vcpu, run);
> + case HSR_EC_CP14_LS:
> + return kvm_handle_cp14_load_store(vcpu, run);
> + case HSR_EC_CP14_64:
> + return kvm_handle_cp14_access(vcpu, run);
> + case HSR_EC_CP_0_13:
> + return kvm_handle_cp_0_13_access(vcpu, run);
> + case HSR_EC_CP10_ID:
> + return kvm_handle_cp10_id(vcpu, run);
> + case HSR_EC_SVC_HYP:
> + /* SVC called from Hyp mode should never get here */
> + kvm_msg("SVC called from Hyp mode shouldn't go here");
> + BUG();
> + case HSR_EC_HVC:
> + kvm_msg("hvc: %x (at %08x)", vcpu->arch.hsr & ((1 << 16) - 1),
> + vcpu->arch.regs.pc);
> + kvm_msg(" HSR: %8x", vcpu->arch.hsr);
> + break;
> + case HSR_EC_IABT:
> + case HSR_EC_DABT:
> + return kvm_handle_guest_abort(vcpu, run);
> + case HSR_EC_IABT_HYP:
> + case HSR_EC_DABT_HYP:
> + /* The hypervisor should never cause aborts */
> + kvm_msg("The hypervisor itself shouldn't cause aborts");
> + BUG();
> + default:
> + kvm_msg("Unkown exception class: %08x (%08x)", hsr_ec,
> + vcpu->arch.hsr);
> + BUG();
> + }
x86 uses a function table, which is slightly nicer.
> +
> + return 0;
> +}
> +
> /**
> * kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code
> * @vcpu: The VCPU pointer
> @@ -333,6 +390,26 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu,
> struct kvm_run *run)
> local_irq_enable();
>
> trace_kvm_exit(vcpu->arch.regs.pc);
> +
> + ret = handle_exit(vcpu, run, ret);
> + if (ret) {
> + kvm_err(ret, "Error in handle_exit");
> + break;
> + }
> +
> + if (run->exit_reason == KVM_EXIT_MMIO)
> + break;
> +
> + if (need_resched()) {
> + vcpu_put(vcpu);
> + schedule();
> + vcpu_load(vcpu);
> + }
I don't think you need the vcpu_put()/vcpu_load() here; you can replace
the whole thing with cond_resched().
> +
> + if (signal_pending(current) && !(run->exit_reason)) {
> + run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
This exit reason doesn't fit with KVM_IRQ_LINE.
With KVM_INTERRUPT, userspace is responsible for determining when to
inject interrupts, so it needs to know when guest interrupts become
enabled (this is KVM_EXIT_IRQ_WINDOWS_OPEN). With KVM_IRQ_LINE,
userspace just sets the line status, and the kernel takes care of
everything.
Oh, and you need to exit to userspace unconditionally if a signal is
pending.
> + break;
> + }
> }
>
> +
> +/******************************************************************************
> + * Co-processor emulation
> + */
> +
> +struct coproc_params {
> + unsigned long CRm;
> + unsigned long CRn;
> + unsigned long Op1;
> + unsigned long Op2;
> + unsigned long Rt1;
> + unsigned long Rt2;
> + bool is_64bit;
> + bool is_write;
> +};
> +
> +#define CP15_OP(_vcpu, _params, _cp15_reg) \
> +do { \
> + if (_params->is_write) \
> + _vcpu->arch.cp15._cp15_reg = *vcpu_reg(_vcpu, _params->Rt1); \
> + else \
> + *vcpu_reg(_vcpu, _params->Rt1) = _vcpu->arch.cp15._cp15_reg; \
> +} while (0);
Ugly. How about an array of registers instead?
--
error compiling committee.c: too many arguments to function
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