KVM: PPC: BOOK3S: HV: Use base page size when comparing against slb value

With guests supporting Multiple page size per segment (MPSS),
hpte_page_size returns the actual page size used. Add a new function to
return base page size and use that to compare against the the page size
calculated from SLB. Without this patch a hpte lookup can fail since
we are comparing wrong page size in kvmppc_hv_find_lock_hpte.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

3 files changed, 20 insertions, 8 deletions

diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index fddb72b48ce9..d645428a65a4 100644
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -198,8 +198,10 @@ static inline unsigned long compute_tlbie_rb(unsigned long v, unsigned long r,
         return rb;
 }
 
-static inline unsigned long hpte_page_size(unsigned long h, unsigned long l)
+static inline unsigned long __hpte_page_size(unsigned long h, unsigned long l,
+                                             bool is_base_size)
 {
+
         int size, a_psize;
         /* Look at the 8 bit LP value */
         unsigned int lp = (l >> LP_SHIFT) & ((1 << LP_BITS) - 1);
@@ -214,14 +216,27 @@ static inline unsigned long hpte_page_size(unsigned long h, unsigned long l)
                                 continue;
 
                         a_psize = __hpte_actual_psize(lp, size);
-                        if (a_psize != -1)
+                        if (a_psize != -1) {
+                                if (is_base_size)
+                                        return 1ul << mmu_psize_defs[size].shift;
                                 return 1ul << mmu_psize_defs[a_psize].shift;
+                        }
                 }
 
         }
         return 0;
 }
 
+static inline unsigned long hpte_page_size(unsigned long h, unsigned long l)
+{
+        return __hpte_page_size(h, l, 0);
+}
+
+static inline unsigned long hpte_base_page_size(unsigned long h, unsigned long l)
+{
+        return __hpte_page_size(h, l, 1);
+}
+
 static inline unsigned long hpte_rpn(unsigned long ptel, unsigned long psize)
 {
         return ((ptel & HPTE_R_RPN) & ~(psize - 1)) >> PAGE_SHIFT;
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 80561074078d..68468d695f12 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -1562,7 +1562,7 @@ static ssize_t kvm_htab_write(struct file *file, const char __user *buf,
                                 goto out;
                         }
                         if (!rma_setup && is_vrma_hpte(v)) {
-                                unsigned long psize = hpte_page_size(v, r);
+                                unsigned long psize = hpte_base_page_size(v, r);
                                 unsigned long senc = slb_pgsize_encoding(psize);
                                 unsigned long lpcr;
 
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 6e6224318c36..5a24d3c2b6b8 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -814,13 +814,10 @@ long kvmppc_hv_find_lock_hpte(struct kvm *kvm, gva_t eaddr, unsigned long slb_v,
                         r = hpte[i+1];
 
                         /*
-                         * Check the HPTE again, including large page size
-                         * Since we don't currently allow any MPSS (mixed
-                         * page-size segment) page sizes, it is sufficient
-                         * to check against the actual page size.
+                         * Check the HPTE again, including base page size
                          */
                         if ((v & valid) && (v & mask) == val &&
-                            hpte_page_size(v, r) == (1ul << pshift))
+                            hpte_base_page_size(v, r) == (1ul << pshift))
                                 /* Return with the HPTE still locked */
                                 return (hash << 3) + (i >> 1);