Hi Tristan,
Thank you for your comment.
You (Tristan.Gingold) said:
>> I will post patches of PV-on-HVM for IPF.
>>
>> We wrote the patch under this consideration:
>>
>> * Expand hvm_op hypercall
>> + Introduce HVMOP_setup_shared_info_page
>> - A page allocated on HVM-guest OS is swapped original shared_info
>> page with this hypercall.
>> - In x86 code, original shared_info page is used after pv-on-hvm
>> setup with remapping feature in arch depend HYPERVISOR_memory_op.
>> But, we can't implement same feature for IPF, thus we select to
>> implement with this method.
> Can you explain why you can't reuse the HYPERVISOR_memory_op hcall ?
> It isn't clear for me.
In x86 code (xen/arch/x86/mm.c), it uses only virtual space of page frame
allocated by GuestOS, and remaps the vitual space to original share_info
page frame. But, we can't find same method for IPF.
Can you suggest us about the remapping method ?
> About the patch:
> +static int
> +vmx_gnttab_setup_table(unsigned long frame_pa, unsigned long nr_frames)
> +{
> + struct domain *d = current->domain;
> + int rc = 0, i;
> + unsigned long o_grant_shared, pgaddr;
> +
> + if (nr_frames != NR_GRANT_FRAMES) {
> + return -1;
> You'd better to return -EINVAL.
I agree. I'll correct it.
> + }
> + o_grant_shared = (unsigned long)d->grant_table->shared;
> + d->grant_table->shared = (struct grant_entry *)domain_mpa_to_imva(d,
> frame_pa);
> +
> + /* Copy existing grant table shared into new page */
> + if (o_grant_shared) {
> + memcpy((void*)d->grant_table->shared,
> + (void*)o_grant_shared, PAGE_SIZE * nr_frames);
> You should check the result of domain_mpa_to_imva, as it could fail.
I agree. I'll try to correct it. It returns NULL if it fails, I think.
Is it correct ?
> + if (likely(IS_XEN_HEAP_FRAME(virt_to_page(pgaddr)))) {
> + free_domheap_page(virt_to_page(pgaddr));
> + free_xenheap_page((void *)pgaddr);
> + }
> + else {
> + put_page(virt_to_page(pgaddr));
> + }
> May create a function to be called by gnttab_setup_table and
> setup_shared_info_page.
I think that these function are for only VT-i domain, thus I used
vmx_ prefix. What do you think about it ?
Thanks,
-- Tsunehisa Doi
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