Hi Alex
> > Hi Aashish,
> >
> > On 05/21/2012 01:51 PM, Aashish Mittal wrote:
> >> Hi
> >> I'm working on KVM optimizations on Powerpc e500v2 embedded
> >> architecture. For my
> >> project i'm trying to increase the size of shared region mapped my
> >> Magic
> >> Page
> >> between host and guest for paravirtual support. I was expecting this
> >> would
> >> possible since we are using a TLB1 entry to map the magic page entry
> >> inside the
> >> host. I'm trying to increase it's size to 1MB. I've declared a shared
> >> structure
> >> tcache of 1MB similar to vcpu->arch.shared and trying to map it in the
> >> guest
> >> virtual space. The shared page earlier is now the last page of this
> >> tcache
> >> structure.
> >>
> >> This is the modified code :
> >>
> >> Initialization in e500.c in function kvmppc_core_vcpu_create
> >>
> >> shared = (void*)__get_free_pages(GFP_KERNEL|__GFP_ZERO,10);
> >> vcpu->arch.tcache = (void*)(shared);
> >> vcpu->arch.shared = (void*)(shared + (((1<<
> >> 10)-1)<<PAGE_SHIFT));
> >
> > Did you also change the shared page elements to still be within the
> > first page? Otherwise the offset wouldn't fit into the immediate fields
> > of the asm instructions. We can't reach as low as -1MB with all
> > operations.
> >
Since i'm keeping the shared(magic page) to be as the last page of this 1
MB section and trying to map the guest virtual address from 0xfff00000 to
0xffffffff while setting magic.mas2. Won't the magic page remain at it's
original location i.e 0xfffff000 ?
I've not changed anything on the shared page yet so the believe all the
elements would remain to be on the first page , right now i'm just trying
to increase the shared region to 1MB using this modification.
Aashish
> >>
> >>
> >> void kvmppc_map_magic(struct kvm_vcpu *vcpu)
> >> {
> >> struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);
> >> struct kvm_book3e_206_tlb_entry magic;
> >> ulong shared_page = ((ulong)vcpu->arch.tcache)& PAGE_MASK;
> >> ulong page = shared_page;
> >> unsigned int stid;
> >> pfn_t pfn,pfn1;
> >> int i = 0;
> >>
> >> for(i=0;i< 1024;i++){
> >> pfn1 = (pfn_t)virt_to_phys((void *)page)>> PAGE_SHIFT;
> >> get_page(pfn_to_page(pfn1));
> >> page += 0x1000;
> >> }
> >>
> >> pfn = (pfn_t)virt_to_phys((void *)shared_page)>> PAGE_SHIFT;
> >>
> >>
> >> preempt_disable();
> >> stid = e500_get_sid(vcpu_e500, 0, 0, 0, 0);
> >>
> >> magic.mas1 = MAS1_VALID | MAS1_TS | MAS1_TID(stid) |
> >> MAS1_TSIZE(BOOK3E_PAGESZ_1M);
> >> magic.mas2 = (vcpu->arch.magic_page_ea& 0xfff00000)| MAS2_M;
> >>
> >> magic.mas7_3 = ((u64)pfn<< PAGE_SHIFT) |
> >> MAS3_SW | MAS3_SR | MAS3_UW | MAS3_UR;
> >>
> >> __write_host_tlbe(&magic, MAS0_TLBSEL(1) |
> >> MAS0_ESEL(tlbcam_index));
> >> preempt_enable();
> >> }
> >>
> >> But i'm experiencing the following error printed in the guest
> >>
> >> KVM: Live patching for a fast VM worked
> >> initcall kvm_guest_init+0x0/0x1f8 returned with disabled interrupts
> >> initcall migration_init+0x0/0x8c returned with disabled interrupts
> >>
> >> and then the guest just hangs.
> >>
> >> Does anybody have any idea how to map it correctly
> >>
> >> Thanks
> >>
> >>
> >> --
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> >
> >
>
>
> cheers
> Aashish
>
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