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.
> 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.
>
>
> Alex
>
>>
>>
>> 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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