On 10/31/2012 05:18 PM, Sanjay Lal wrote:
> - Implements the arch specific APIs for KVM, some are stubs for MIPS
> - kvm_mips_handle_exit(): Main 'C' distpatch routine for handling exceptions while in "Guest" mode.
> - Also implements in-kernel timer interrupt support for the guest.
>
> +
> +static void
> +kvm_mips_init_tlbs (void *arg)
> +{
> + ulong flags, wired;
> + struct kvm *kvm = (struct kvm *) arg;
> +
> + ENTER_CRITICAL(flags);
> + /* Add a wired entry to the TLB, it is used to map the commpage to the Guest kernel */
> + wired = read_c0_wired();
> + write_c0_wired(wired + 1);
> + mtc0_tlbw_hazard();
> + kvm->arch.commpage_tlb = wired;
> + EXIT_CRITICAL(flags);
> +
Since this is called from smp_call_function(), it is called with
interrupts disabled.
> + kvm_debug("[%d] commpage TLB: %d\n", smp_processor_id(), kvm->arch.commpage_tlb);
> +}
> +
> +int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
> +{
> + int cpu;
> +
> + if (atomic_inc_return(&kvm_mips_instance) == 1) {
> + kvm_info("%s: 1st KVM instance, setup host TLB parameters\n", __func__);
> + for_each_online_cpu(cpu) {
> + smp_call_function_single(cpu, kvm_mips_init_tlbs, kvm, 1);
> + }
Use on_each_cpu() instead.
> + }
> +
> + kvm->arch.gfn_to_pfn = gfn_to_pfn;
> + kvm->arch.release_pfn_clean = kvm_release_pfn_clean;
> + kvm->arch.is_error_pfn = is_error_pfn;
> +
> + return 0;
> +}
> +
> +
> +
> +void kvm_arch_flush_shadow_all(struct kvm *kvm)
> +{
> +}
> +
> +void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
> + struct kvm_memory_slot *slot)
> +{
> +}
> +
> +
Don't you need to flush the shadow tlbs here?
> +
> +ulong kvm_mips_get_ramsize (struct kvm *kvm)
> +{
> + return (kvm->memslots->memslots[0].npages << PAGE_SHIFT);
> +}
What is this?
Slot 0 is not special on other archs.
> +
> +void
> +kvm_arch_flush_shadow(struct kvm *kvm)
> +{
> +}
Flush here too?
> +
> +int
> +kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
> +{
> + int r = 0;
> + sigset_t sigsaved;
> +
> + if (vcpu->sigset_active)
> + sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved);
> +
> + if (vcpu->mmio_needed) {
> + if (!vcpu->mmio_is_write)
> + kvm_mips_complete_mmio_load(vcpu, run);
> + vcpu->mmio_needed = 0;
> + }
> +
> + /* Check if we have any exceptions/interrupts pending */
> + kvm_mips_deliver_interrupts(vcpu, kvm_read_c0_guest_cause(vcpu->arch.cop0));
> +
> + local_irq_disable();
> + kvm_guest_enter();
> +
> + r = __kvm_mips_vcpu_run(run, vcpu);
So you handle all exits with interrupts disabled? What about TLB misses
that need to swap in a page? What about host interrupts?
> +
> + kvm_guest_exit();
> + local_irq_enable();
> +
> + if (vcpu->sigset_active)
> + sigprocmask(SIG_SETMASK, &sigsaved, NULL);
> +
> + return r;
> +}
> +
> +int
> +
> +/*
> + * Return value is in the form (errcode<<2 | RESUME_FLAG_HOST | RESUME_FLAG_NV)
> + */
> +int
> +kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
> +{
> + uint32_t cause = vcpu->arch.host_cp0_cause;
> + uint32_t exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
> + uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc;
> + ulong badvaddr = vcpu->arch.host_cp0_badvaddr;
> + enum emulation_result er = EMULATE_DONE;
> + int ret = RESUME_GUEST;
> +
> + /* Set a default exit reason */
> + run->exit_reason = KVM_EXIT_UNKNOWN;
> + run->ready_for_interrupt_injection = 1;
ready_for_interrupt_injection is an x86ism, you probably don't need it.
> +
> + /* Set the appropriate status bits based on host CPU features, before we hit the scheduler */
> + kvm_mips_set_c0_status();
> +
> + local_irq_enable();
Ah, so you handle exits with interrupts enabled. But that's not how we
usually do it; the standard pattern is
while (can continue)
disable interrupts
enter guest
enable interrupts
process exit
> +
> + kvm_debug("kvm_mips_handle_exit: cause: %#x, PC: %p, kvm_run: %p, kvm_vcpu: %p\n",
> + cause, opc, run, vcpu);
> +
> + /* Do a privilege check, if in UM most of these exit conditions end up
> + * causing an exception to be delivered to the Guest Kernel
> + */
> + er = kvm_mips_check_privilege (cause, opc, run, vcpu);
> + if (er == EMULATE_PRIV_FAIL) {
> + goto skip_emul;
> + }
> + else if (er == EMULATE_FAIL) {
> + run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
> + ret = RESUME_HOST;
> + goto skip_emul;
> + }
> +
> + switch (exccode) {
> + case T_INT:
> + kvm_debug("[%d]T_INT @ %p\n", vcpu->vcpu_id, opc);
> +
> + kvm_mips_account_exit(vcpu, INT_EXITS);
> +
> + if (need_resched()) {
> + cond_resched();
> + }
> +
> + ret = RESUME_GUEST;
> + break;
> +
> + case T_COP_UNUSABLE:
> + kvm_debug("T_COP_UNUSABLE: @ PC: %p\n", opc);
> +
> + kvm_mips_account_exit(vcpu, COP_UNUSABLE_EXITS);
> + ret = kvm_mips_callbacks->handle_cop_unusable(vcpu);
> + /* XXXKYMA: Might need to return to user space */
> + if (run->exit_reason == KVM_EXIT_IRQ_WINDOW_OPEN) {
> + ret = RESUME_HOST;
> + }
> + break;
> +
> + case T_TLB_MOD:
> + kvm_mips_account_exit(vcpu, TLBMOD_EXITS);
> + ret = kvm_mips_callbacks->handle_tlb_mod(vcpu);
> + break;
> +
> + case T_TLB_ST_MISS:
> + kvm_debug("TLB ST fault: cause %#x, status %#lx, PC: %p, BadVaddr: %#lx\n",
> + cause, kvm_read_c0_guest_status(vcpu->arch.cop0), opc, badvaddr);
> +
> + kvm_mips_account_exit(vcpu, TLBMISS_ST_EXITS);
> + ret = kvm_mips_callbacks->handle_tlb_st_miss(vcpu);
> + break;
> +
> + case T_TLB_LD_MISS:
> + kvm_debug("TLB LD fault: cause %#x, PC: %p, BadVaddr: %#lx\n", cause, opc, badvaddr);
> +
> + kvm_mips_account_exit(vcpu, TLBMISS_LD_EXITS);
> + ret = kvm_mips_callbacks->handle_tlb_ld_miss(vcpu);
> + break;
> +
> + case T_ADDR_ERR_ST:
> + kvm_mips_account_exit(vcpu, ADDRERR_ST_EXITS);
> + ret = kvm_mips_callbacks->handle_addr_err_st(vcpu);
> + break;
> +
> + case T_ADDR_ERR_LD:
> + kvm_mips_account_exit(vcpu, ADDRERR_LD_EXITS);
> + ret = kvm_mips_callbacks->handle_addr_err_ld(vcpu);
> + break;
> +
> + case T_SYSCALL:
> + kvm_mips_account_exit(vcpu, SYSCALL_EXITS);
> + ret = kvm_mips_callbacks->handle_syscall(vcpu);
> + break;
> +
> + case T_RES_INST:
> + kvm_mips_account_exit(vcpu, RESVD_INST_EXITS);
> + ret = kvm_mips_callbacks->handle_res_inst(vcpu);
> + break;
> +
> + case T_BREAK:
> + kvm_mips_account_exit(vcpu, BREAK_INST_EXITS);
> + ret = kvm_mips_callbacks->handle_break(vcpu);
> + break;
> +
> + default:
> + kvm_err("Exception Code: %d, not yet handled, @ PC: %p, inst: 0x%08x BadVaddr: %#lx Status: %#lx\n",
> + exccode, opc, kvm_get_inst(opc, vcpu), badvaddr, kvm_read_c0_guest_status(vcpu->arch.cop0));
> + kvm_arch_vcpu_dump_regs(vcpu);
> + run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
> + ret = RESUME_HOST;
> + break;
> +
> + }
> +
> +skip_emul:
> + local_irq_disable();
> +
> + if (er == EMULATE_DONE && !(ret & RESUME_HOST))
> + kvm_mips_deliver_interrupts(vcpu, cause);
> +
> + if (!(ret & RESUME_HOST)) {
> + /* Only check for signals if not already exiting to userspace */
> + if (signal_pending(current)) {
> + run->exit_reason = KVM_EXIT_INTR;
> + ret = (-EINTR << 2) | RESUME_HOST;
> + kvm_mips_account_exit(vcpu, SIGNAL_EXITS);
> + }
> + }
> +
> + return (ret);
> +}
> +void
> +kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
> +{
> + kvm_mips_vcpu_load(vcpu, cpu);
No need for indirection, just fold these two functions.
> + return;
> +}
> +
> +void
> +kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
> +{
> + /* During VM shutdown */
> + if (!vcpu)
> + return;
Hmm, shouldn't happen.
> +
> + kvm_mips_vcpu_put(vcpu);
> + return;
> +}
> +
> +
> +
> +int __init
> +kvm_mips_init(void)
> +{
> + int ret;
> +
> + ret = kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);
> +
> + if (ret)
> + return (ret);
> +
> + printk("KVM/MIPS Initialized\n");
> + return (0);
> +}
> +
> +void __exit
> +kvm_mips_exit(void)
> +{
> + kvm_exit();
> + printk("KVM/MIPS unloaded\n");
> +}
> +
> +module_init(kvm_mips_init);
> +module_exit(kvm_mips_exit);
>
--
error compiling committee.c: too many arguments to function
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