å 2015-07-06, Mon, 15:44:53 ,Andrew Cooper ååï
On 06/07/2015 08:22, xinyue wrote:
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Hi,
ÂÂÂ For I want to translate the virtual address in HVM
DomU to virtual address in Xen. But when I use the
function paging_gva_to_gfn and get_gfn, I can feel the
performance down quickly, the machine become very hot and
then I have to force the machine shutting down.
Your machine clearly isn't cooled sufficiently, which is the
first problem.
The codes I used as
below:
ÂÂÂ uint32_t pfec = PFEC_page_present;
ÂÂÂ unsigned long gfn;
ÂÂÂ unsigned long mfn;
ÂÂÂ unsigned long virtaddr;
ÂÂÂ struct vcpu *vcpu = current;
ÂÂÂ struct domain *d = vcpu->domain;
ÂÂÂ gfn = paging_gva_to_gfn(current, 0xc0290000,
&pfec);
ÂÂÂ mfn = get_gfn(d, gfn, &t);
ÂÂÂ virtaddr = map_domain_page(mfn_x(mfn));
I also use the dbg_hvm_va2mfn function in debug.c,
performance problem still present.
Walking pagetables in software is slow. There is no getting
around this.
Your performance problems will be caused by performing the
operation far too often. You should find a way to reduce this.
Thanks very much, I think I only do this for just once. And
after the thanslation is done, the performance is not turn to
normal. Does that mean that if I wait long enough it will
recovery?
