Re: [PATCH 13/22] KVM: X86: Add kvm_read_guest_page_tdp function

Avi Kivity
2010-04-27T12:42:29Z

On 04/27/2010 01:38 PM, Joerg Roedel wrote:
> This patch adds a function which can read from the guests
> physical memory or from the guest's guest physical memory.
> This will be used in the two-dimensional page table walker.
>
> Signed-off-by: Joerg Roedel<joerg.roedel@amd.com>
> ---
> arch/x86/include/asm/kvm_host.h | 3 +++
> arch/x86/kvm/x86.c | 24 ++++++++++++++++++++++++
> 2 files changed, 27 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 3cbfb51..7851bbc 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -635,6 +635,9 @@ void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr);
> void kvm_requeue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code);
> void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long cr2,
> u32 error_code);
> +int kvm_read_guest_page_tdp(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
> + gfn_t gfn, void *data, int offset, int len,
> + u32 *error);
> bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl);
>
> int kvm_pic_set_irq(void *opaque, int irq, int level);
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 6b2ce1d..558d995 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -356,6 +356,30 @@ bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl)
> EXPORT_SYMBOL_GPL(kvm_require_cpl);
>
> /*
> + * This function will be used to read from the physical memory of the currently
> + * running guest. The difference to kvm_read_guest_page ist that this function
> + * can read from guest physical or from the guest's guest physical memory.
> + */
>

s/ist/is/

> +int kvm_read_guest_page_tdp(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
> + gfn_t gfn, void *data, int offset, int len,
> + u32 *error)
>

Naming: I see 'tdp' as a host property, and this is valid whether tdp is
enabled or not. Suggest calling it kvm_read_nested_guest_page().

Following mmu.txt, the parameter would be ngfn, not gfn.

> +{
> + gfn_t real_gfn;
> + gpa_t gpa;
> +
> + *error = 0;
> + gpa = gfn<< PAGE_SHIFT;
> + real_gfn = mmu->translate_gpa(vcpu, gpa, error);
>

Overflow: sizeof(gpa) > sizeof(gfn).

> + if (real_gfn == UNMAPPED_GVA)
> + return -EFAULT;
> +
> + real_gfn>>= PAGE_SHIFT;
>

gpa_to_gfn().

> +
> + return kvm_read_guest_page(vcpu->kvm, real_gfn, data, offset, len);
> +}
> +EXPORT_SYMBOL_GPL(kvm_read_guest_page_tdp);
> +
>

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