KVM: PPC: Book3S PR: Preserve storage control bits

PR KVM page fault handler performs eaddr to pte translation for a guest,
however kvmppc_mmu_book3s_64_xlate() does not preserve WIMG bits
(storage control) in the kvmppc_pte struct. If PR KVM is running as
a second level guest under HV KVM, and PR KVM tries inserting HPT entry,
this fails in HV KVM if it already has this mapping.

This preserves WIMG bits between kvmppc_mmu_book3s_64_xlate() and
kvmppc_mmu_map_page().

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 2acc691..0f3ac09 100644 (file)
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -342,6 +342,7 @@ struct kvmppc_pte {
        bool may_read           : 1;
        bool may_write          : 1;
        bool may_execute        : 1;
+       unsigned long wimg;
        u8 page_size;           /* MMU_PAGE_xxx */
 };
 

diff --git a/arch/powerpc/kvm/book3s_64_mmu.c b/arch/powerpc/kvm/book3s_64_mmu.c
index 7015357..29ebe2f 100644 (file)
--- a/arch/powerpc/kvm/book3s_64_mmu.c
+++ b/arch/powerpc/kvm/book3s_64_mmu.c
@@ -319,6 +319,7 @@ do_second:
                gpte->may_execute = true;
        gpte->may_read = false;
        gpte->may_write = false;
+       gpte->wimg = r & HPTE_R_WIMG;
 
        switch (pp) {
        case 0:

diff --git a/arch/powerpc/kvm/book3s_64_mmu_host.c b/arch/powerpc/kvm/book3s_64_mmu_host.c
index 4b4e927..145a618 100644 (file)
--- a/arch/powerpc/kvm/book3s_64_mmu_host.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_host.c
@@ -145,6 +145,8 @@ int kvmppc_mmu_map_page(struct kvm_vcpu *vcpu, struct kvmppc_pte *orig_pte,
        else
                kvmppc_mmu_flush_icache(pfn);
 
+       rflags = (rflags & ~HPTE_R_WIMG) | orig_pte->wimg;
+
        /*
         * Use 64K pages if possible; otherwise, on 64K page kernels,
         * we need to transfer 4 more bits from guest real to host real addr.

diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index ce437b9..f026b06 100644 (file)
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -537,7 +537,7 @@ int kvmppc_handle_pagefault(struct kvm_run *run, struct kvm_vcpu *vcpu,
        int r = RESUME_GUEST;
        int relocated;
        int page_found = 0;
-       struct kvmppc_pte pte;
+       struct kvmppc_pte pte = { 0 };
        bool dr = (kvmppc_get_msr(vcpu) & MSR_DR) ? true : false;
        bool ir = (kvmppc_get_msr(vcpu) & MSR_IR) ? true : false;
        u64 vsid;