Lai Jiangshan wrote: > Lai Jiangshan wrote: >> RFC, because maybe I missing something with the old code. >> >> Frome: Lai Jiangshan <laijs@xxxxxxxxxxxxxx> >> >> In Document/kvm/mmu.txt: >> gfn: >> Either the guest page table containing the translations shadowed by this >> page, or the base page frame for linear translations. See role.direct. >> >> But in function FNAME(fetch)(), sp->gfn is incorrect when one of following >> situations occurred: >> 1) guest is 32bit paging and guest uses pse-36 and the guest PDE maps >> a 4-MByte page(backed by 4k host pages) and bits 20:13 of the guest PDE >> is not equals to 0. >> 2) guest is long mode paging and the guest PDPTE maps a 1-GByte page >> (backed by 4k or 2M host pages) >> > > Resend this patch with the changelog changed. > > As Marcelo Tosatti and Gui Jianfeng points out, > FNAME(fetch)() miss quadrant on 4mb large page emulation with shadow. > > Subject: [PATCH] kvm: calculate correct gfn for small host pages which emulates large guest pages > > In Document/kvm/mmu.txt: > gfn: > Either the guest page table containing the translations shadowed by this > page, or the base page frame for linear translations. See role.direct. > > But in function FNAME(fetch)(), sp->gfn is incorrect when one of following > situations occurred: > 1) guest is 32bit paging and the guest PDE maps a 4-MByte page > (backed by 4k host pages), FNAME(fetch)() miss handling the quadrant. > > And if guest use pse-36, "table_gfn = gpte_to_gfn(gw->ptes[level - delta]);" > is incorrect. > 2) guest is long mode paging and the guest PDPTE maps a 1-GByte page > (backed by 4k or 2M host pages). > > So we fix it to suit to the document and suit to the code which > requires sp->gfn correct when sp->role.direct=1. > > We use the goal mapping gfn(gw->gfn) to calculate the base page frame > for linear translations, it is simple and easy to be understood. > > Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx> > --- Could you add these: Reported-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx> Reported-by: Gui Jianfeng <guijianfeng@xxxxxxxxxxxxxx> Thanks. Lai. PS. The whole patches includes: [PATCH] kvm mmu: reduce 50% memory usage [PATCH] kvm: calculate correct gfn for small host pages which emulates large guest pages [PATCH] kvm, tdp: calculate correct base gfn for non-DIR level [PATCH] kvm: update document of gfns -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
