Re: [PATCH 3/5] KVM: Add paravirt MMU write support

Avi Kivity
2007-06-18T08:20:49Z

Anthony Liguori wrote:
> +static int kvm_hypercall_mmu_write(struct kvm_vcpu *vcpu, gva_t addr,
> + unsigned long size, unsigned long a0,
> + unsigned long a1)
> +{
> + gpa_t gpa = vcpu->mmu.gva_to_gpa(vcpu, addr);
> + u64 value;
> +
> + if (gpa == UNMAPPED_GVA)
> + return -EFAULT;
> + if (size == 1) {
> + if (!emulator_write_phys(vcpu, gpa, &a0, sizeof(a0)))
> + return -EFAULT;
> + } else if (size == 2) {
> + value = (u64)a1 << 32 | a0;
> + if (!emulator_write_phys(vcpu, gpa, &value, sizeof(value)))
> + return -EFAULT;
> + } else
> + return -E2BIG;
> +
> + return 0;
> +}

Hypercalls should return kvm-specific error codes (defined in
include/linux/kvm_para.h), not Linux error codes, as they could be used
in operating systems which have different values for E2BIG and friends.

> +static void kvm_pte_clear(struct mm_struct *mm,
> + unsigned long addr, pte_t *ptep)
> +{
> + pte_t pte = {0};
>

Surely there's a nice macro for creating a pte from an int?

Any performance measurement?

--
error compiling committee.c: too many arguments to function