This is a note to let you know that I've just added the patch titled

KVM: PPC: Book3S PR: Fix WIMG handling under pHyp

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: kvm-ppc-book3s-pr-fix-wimg-handling-under-phyp.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 6c7d47c33ed323f14f2a3b8de925e831dbaa4e69 Mon Sep 17 00:00:00 2001

From: Alexey Kardashevskiy aik@ozlabs.ru Date: Wed, 22 Nov 2017 14:42:21 +1100 Subject: KVM: PPC: Book3S PR: Fix WIMG handling under pHyp

From: Alexey Kardashevskiy aik@ozlabs.ru

commit 6c7d47c33ed323f14f2a3b8de925e831dbaa4e69 upstream.

Commit 96df226 ("KVM: PPC: Book3S PR: Preserve storage control bits") added code to preserve WIMG bits 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 was 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").

According to LoPAPR v1.1 14.5.4.1.2 H_ENTER:

The hypervisor checks that the WIMG bits within the PTE are appropriate for the physical page number else H_Parameter return. (For System Memory pages WIMG=0010, or, 1110 if the SAO option is enabled, and for IO pages WIMG=01**.)

This hence initializes WIMG to non-zero value HPTE_R_M (0x10), as expected by pHyp.

[paulus@ozlabs.org - fix compile for 32-bit]

Fixes: 96df226 "KVM: PPC: Book3S PR: Preserve storage control bits" Signed-off-by: Alexey Kardashevskiy aik@ozlabs.ru Tested-by: Ruediger Oertel ro@suse.de Reviewed-by: Greg Kurz groug@kaod.org Tested-by: Greg Kurz groug@kaod.org Signed-off-by: Paul Mackerras paulus@ozlabs.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/powerpc/kvm/book3s_64_mmu.c | 1 + arch/powerpc/kvm/book3s_pr.c | 2 ++ 2 files changed, 3 insertions(+)

--- a/arch/powerpc/kvm/book3s_64_mmu.c +++ b/arch/powerpc/kvm/book3s_64_mmu.c @@ -235,6 +235,7 @@ static int kvmppc_mmu_book3s_64_xlate(st gpte->may_read = true; gpte->may_write = true; gpte->page_size = MMU_PAGE_4K; + gpte->wimg = HPTE_R_M;

return 0; } --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -60,6 +60,7 @@ static void kvmppc_giveup_fac(struct kvm #define MSR_USER32 MSR_USER #define MSR_USER64 MSR_USER #define HW_PAGE_SIZE PAGE_SIZE +#define HPTE_R_M _PAGE_COHERENT #endif

static bool kvmppc_is_split_real(struct kvm_vcpu *vcpu) @@ -557,6 +558,7 @@ int kvmppc_handle_pagefault(struct kvm_r pte.eaddr = eaddr; pte.vpage = eaddr >> 12; pte.page_size = MMU_PAGE_64K; + pte.wimg = HPTE_R_M; }

switch (kvmppc_get_msr(vcpu) & (MSR_DR|MSR_IR)) {

Patches currently in stable-queue which might be from aik@ozlabs.ru are

queue-4.14/kvm-ppc-book3s-pr-fix-wimg-handling-under-phyp.patch