summaryrefslogtreecommitdiffstats
path: root/arch/powerpc
diff options
context:
space:
mode:
authorAlexander Graf <agraf@suse.de>2014-05-12 01:08:32 +0200
committerAlexander Graf <agraf@suse.de>2014-05-30 14:26:24 +0200
commitf3383cf80e417e86fcc84a2eb4c96bc52842d8d9 (patch)
tree69cde42c1f516992ef2e6db665d1098ee0eac951 /arch/powerpc
parent1f365bb0de12da4a9ef8e56ffba2218d9a026011 (diff)
downloadop-kernel-dev-f3383cf80e417e86fcc84a2eb4c96bc52842d8d9.zip
op-kernel-dev-f3383cf80e417e86fcc84a2eb4c96bc52842d8d9.tar.gz
KVM: PPC: Disable NX for old magic page using guests
Old guests try to use the magic page, but map their trampoline code inside of an NX region. Since we can't fix those old kernels, try to detect whether the guest is sane or not. If not, just disable NX functionality in KVM so that old guests at least work at all. For newer guests, add a bit that we can set to keep NX functionality available. Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/include/asm/kvm_host.h1
-rw-r--r--arch/powerpc/include/uapi/asm/kvm_para.h6
-rw-r--r--arch/powerpc/kvm/book3s_64_mmu.c3
-rw-r--r--arch/powerpc/kvm/powerpc.c14
4 files changed, 22 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 29fbb55..bb66d8b 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -631,6 +631,7 @@ struct kvm_vcpu_arch {
#endif
unsigned long magic_page_pa; /* phys addr to map the magic page to */
unsigned long magic_page_ea; /* effect. addr to map the magic page to */
+ bool disable_kernel_nx;
int irq_type; /* one of KVM_IRQ_* */
int irq_cpu_id;
diff --git a/arch/powerpc/include/uapi/asm/kvm_para.h b/arch/powerpc/include/uapi/asm/kvm_para.h
index e3af328..91e42f0 100644
--- a/arch/powerpc/include/uapi/asm/kvm_para.h
+++ b/arch/powerpc/include/uapi/asm/kvm_para.h
@@ -82,10 +82,16 @@ struct kvm_vcpu_arch_shared {
#define KVM_FEATURE_MAGIC_PAGE 1
+/* Magic page flags from host to guest */
+
#define KVM_MAGIC_FEAT_SR (1 << 0)
/* MASn, ESR, PIR, and high SPRGs */
#define KVM_MAGIC_FEAT_MAS0_TO_SPRG7 (1 << 1)
+/* Magic page flags from guest to host */
+
+#define MAGIC_PAGE_FLAG_NOT_MAPPED_NX (1 << 0)
+
#endif /* _UAPI__POWERPC_KVM_PARA_H__ */
diff --git a/arch/powerpc/kvm/book3s_64_mmu.c b/arch/powerpc/kvm/book3s_64_mmu.c
index 278729f..774a253 100644
--- a/arch/powerpc/kvm/book3s_64_mmu.c
+++ b/arch/powerpc/kvm/book3s_64_mmu.c
@@ -313,6 +313,9 @@ do_second:
gpte->raddr = (r & HPTE_R_RPN & ~eaddr_mask) | (eaddr & eaddr_mask);
gpte->page_size = pgsize;
gpte->may_execute = ((r & HPTE_R_N) ? false : true);
+ if (unlikely(vcpu->arch.disable_kernel_nx) &&
+ !(kvmppc_get_msr(vcpu) & MSR_PR))
+ gpte->may_execute = true;
gpte->may_read = false;
gpte->may_write = false;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index b4e15bf..154f352c 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -177,8 +177,18 @@ int kvmppc_kvm_pv(struct kvm_vcpu *vcpu)
vcpu->arch.shared_big_endian = shared_big_endian;
#endif
- vcpu->arch.magic_page_pa = param1;
- vcpu->arch.magic_page_ea = param2;
+ if (!(param2 & MAGIC_PAGE_FLAG_NOT_MAPPED_NX)) {
+ /*
+ * Older versions of the Linux magic page code had
+ * a bug where they would map their trampoline code
+ * NX. If that's the case, remove !PR NX capability.
+ */
+ vcpu->arch.disable_kernel_nx = true;
+ kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
+ }
+
+ vcpu->arch.magic_page_pa = param1 & ~0xfffULL;
+ vcpu->arch.magic_page_ea = param2 & ~0xfffULL;
r2 = KVM_MAGIC_FEAT_SR | KVM_MAGIC_FEAT_MAS0_TO_SPRG7;
OpenPOWER on IntegriCloud