KVM: e500: track host-writability of pages

Add the possibility of marking a page so that the UW and SW bits are
force-cleared.  This is stored in the private info so that it persists
across multiple calls to kvmppc_e500_setup_stlbe.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/powerpc/kvm/e500.h b/arch/powerpc/kvm/e500.h
index 6d0d329cbb35c2321c7ad3a9e4ec65ad65b899e7..f9acf866c709e99ca8ca6c3cc39a6ae6f83b28e6 100644 (file)
--- a/arch/powerpc/kvm/e500.h
+++ b/arch/powerpc/kvm/e500.h
@@ -34,6 +34,8 @@ enum vcpu_ftr {
 #define E500_TLB_BITMAP                (1 << 30)
 /* TLB1 entry is mapped by host TLB0 */
 #define E500_TLB_TLB0          (1 << 29)
+/* entry is writable on the host */
+#define E500_TLB_WRITABLE      (1 << 28)
 /* bits [6-5] MAS2_X1 and MAS2_X0 and [4-0] bits for WIMGE */
 #define E500_TLB_MAS2_ATTR     (0x7f)
 

diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index c266c02f120f867f211b8088e8e217ff4c64c502..b1be39639d4a1c203f7939b89db63ffdaef96f66 100644 (file)
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c
@@ -45,11 +45,14 @@ static inline unsigned int tlb1_max_shadow_size(void)
        return host_tlb_params[1].entries - tlbcam_index - 1;
 }
 
-static inline u32 e500_shadow_mas3_attrib(u32 mas3, int usermode)
+static inline u32 e500_shadow_mas3_attrib(u32 mas3, bool writable, int usermode)
 {
        /* Mask off reserved bits. */
        mas3 &= MAS3_ATTRIB_MASK;
 
+       if (!writable)
+               mas3 &= ~(MAS3_UW|MAS3_SW);
+
 #ifndef CONFIG_KVM_BOOKE_HV
        if (!usermode) {
                /* Guest is in supervisor mode,
@@ -244,10 +247,13 @@ static inline int tlbe_is_writable(struct kvm_book3e_206_tlb_entry *tlbe)
 
 static inline void kvmppc_e500_ref_setup(struct tlbe_ref *ref,
                                         struct kvm_book3e_206_tlb_entry *gtlbe,
-                                        kvm_pfn_t pfn, unsigned int wimg)
+                                        kvm_pfn_t pfn, unsigned int wimg,
+                                        bool writable)
 {
        ref->pfn = pfn;
        ref->flags = E500_TLB_VALID;
+       if (writable)
+               ref->flags |= E500_TLB_WRITABLE;
 
        /* Use guest supplied MAS2_G and MAS2_E */
        ref->flags |= (gtlbe->mas2 & MAS2_ATTRIB_MASK) | wimg;
@@ -303,6 +309,7 @@ static void kvmppc_e500_setup_stlbe(
 {
        kvm_pfn_t pfn = ref->pfn;
        u32 pr = vcpu->arch.shared->msr & MSR_PR;
+       bool writable = !!(ref->flags & E500_TLB_WRITABLE);
 
        BUG_ON(!(ref->flags & E500_TLB_VALID));
 
@@ -310,7 +317,7 @@ static void kvmppc_e500_setup_stlbe(
        stlbe->mas1 = MAS1_TSIZE(tsize) | get_tlb_sts(gtlbe) | MAS1_VALID;
        stlbe->mas2 = (gvaddr & MAS2_EPN) | (ref->flags & E500_TLB_MAS2_ATTR);
        stlbe->mas7_3 = ((u64)pfn << PAGE_SHIFT) |
-                       e500_shadow_mas3_attrib(gtlbe->mas7_3, pr);
+                       e500_shadow_mas3_attrib(gtlbe->mas7_3, writable, pr);
 }
 
 static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
@@ -487,7 +494,7 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
        }
        local_irq_restore(flags);
 
-       kvmppc_e500_ref_setup(ref, gtlbe, pfn, wimg);
+       kvmppc_e500_ref_setup(ref, gtlbe, pfn, wimg, true);
        kvmppc_e500_setup_stlbe(&vcpu_e500->vcpu, gtlbe, tsize,
                                ref, gvaddr, stlbe);
        writable = tlbe_is_writable(stlbe);