Re: [RFC PATCH kernel] KVM: PPC: Book3S PR: Fix WIMG handling under pHyp

On Wed, Nov 22, 2017 at 02:42:21PM +1100, Alexey Kardashevskiy wrote:

96df226 "KVM: PPC: Book3S PR: Preserve storage control bits" added WIMG
bits preserving but it missed 2 special cases:
- a magic page in kvmppc_mmu_book3s_64_xlate() and
- guest real mode in kvmppc_handle_pagefault().

For these ptes WIMG were 0 and pHyp failed on these causing a guest to
stop in the very beginning at NIP=0x100 (due to bd9166ffe
"KVM: PPC: Book3S PR: Exit KVM on failed mapping").

This initializes WIMG to non-zero value HPTE_R_M. The value is chosen
as (0x192 & HPTE_R_WIMG); 0x192 is a magic value from
kvmppc_mmu_map_page().

Fixes: 96df226 "KVM: PPC: Book3S PR: Preserve storage control bits"
Signed-off-by: Alexey Kardashevskiy <redacted>

Thanks, applied to my kvm-ppc-fixes branch, with an updated commit
message, fixes: tag, and cc:stable@vger.kernel.org.

Paul.