On 08/06/2011 01:39 PM, Christoffer Dall wrote:
Provides complete world-switch implementation to switch to other guests
runinng in non-secure modes. Includes Hyp exception handlers that
captures necessary exception information and stores the information on
the VCPU and KVM structures.
Switching to Hyp mode is done through a simple HVC instructions. The
exception vector code will check that the HVC comes from VMID==0 and if
so will store the necessary state on the Hyp stack, which will look like
this (see hyp_hvc):
...
Hyp_Sp + 4: lr_usr
Hyp_Sp : spsr (Host-SVC cpsr)
When returning from Hyp mode to SVC mode, another HVC instruction is
executed from Hyp mode, which is taken in the Hyp_Svc handler. The Hyp
stack pointer should be where it was left from the above initial call,
since the values on the stack will be used to restore state (see
hyp_svc).
Otherwise, the world-switch is pretty straight-forward. All state that
can be modified by the guest is first backed up on the Hyp stack and the
VCPU values is loaded onto the hardware. State, which is not loaded, but
theoretically modifiable by the guest is protected through the
virtualiation features to generate a trap and cause software emulation.
Upon guest returns, all state is restored from hardware onto the VCPU
struct and the original state is restored from the Hyp-stack onto the
hardware.
One controversy may be the back-door call to __irq_svc (the host
kernel's own physical IRQ handler) which is called when a physical IRQ
exception is taken in Hyp mode while running in the guest.
void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
{
+ unsigned long start, end;
+
latest_vcpu = NULL;
- KVMARM_NOT_IMPLEMENTED();
+
+ start = (unsigned long)vcpu,
+ end = start + sizeof(struct kvm_vcpu);
+ remove_hyp_mappings(kvm_hyp_pgd, start, end);
What if vcpu shares a page with another mapped structure?
+
+ kmem_cache_free(kvm_vcpu_cache, vcpu);
}
return 0;
}
+/**
+ * kvm_arch_vcpu_ioctl_run - the main VCPU run function to execute guest code
+ * @vcpu: The VCPU pointer
+ * @run: The kvm_run structure pointer used for userspace state exchange
+ *
+ * This function is called through the VCPU_RUN ioctl called from user space. It
+ * will execute VM code in a loop until the time slice for the process is used
+ * or some emulation is needed from user space in which case the function will
+ * return with return value 0 and with the kvm_run structure filled in with the
+ * required data for the requested emulation.
+ */
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
- KVMARM_NOT_IMPLEMENTED();
- return -EINVAL;
+ unsigned long flags;
+ int ret;
+
+ for (;;) {
+ trace_kvm_entry(vcpu->arch.regs.pc);
+ debug_ws_enter(vcpu->arch.regs.pc);
why both trace_kvm and debug_ws?
+ kvm_guest_enter();
+
+ local_irq_save(flags);
local_irq_disable() is likely sufficient - the call path never changes.
+ ret = __kvm_vcpu_run(vcpu);
+ local_irq_restore(flags);
+
+ kvm_guest_exit();
+ debug_ws_exit(vcpu->arch.regs.pc);
+ trace_kvm_exit(vcpu->arch.regs.pc);
+ }
+
+ return ret;
}
--
error compiling committee.c: too many arguments to function
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