Re: [PATCH 6/6 v2] kvm: powerpc: use caching attributes as per linux pte

KVM uses same WIM tlb attributes as the corresponding qemu pte.
For this we now search the linux pte for the requested page and
get these cache caching/coherency attributes from pte.

Signed-off-by: Bharat Bhushan <redacted>
---
v1->v2
  - Use Linux pte for wimge rather than RAM/no-RAM mechanism

  arch/powerpc/include/asm/kvm_host.h |    2 +-
  arch/powerpc/kvm/booke.c            |    2 +-
  arch/powerpc/kvm/e500.h             |    8 +++++---
  arch/powerpc/kvm/e500_mmu_host.c    |   31 ++++++++++++++++++-------------
  4 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 3328353..583d405 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h

@@ -535,6 +535,7 @@ struct kvm_vcpu_arch {
  #endif
  	gpa_t paddr_accessed;
  	gva_t vaddr_accessed;
+	pgd_t *pgdir;

  	u8 io_gpr; /* GPR used as IO source/target */
  	u8 mmio_is_bigendian;

@@ -592,7 +593,6 @@ struct kvm_vcpu_arch {
  	struct list_head run_list;
  	struct task_struct *run_task;
  	struct kvm_run *kvm_run;
-	pgd_t *pgdir;

  	spinlock_t vpa_update_lock;
  	struct kvmppc_vpa vpa;

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 17722d8..ebcccc2 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c

@@ -697,7 +697,7 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
  #endif

  	kvmppc_fix_ee_before_entry();
-
+	vcpu->arch.pgdir = current->mm->pgd;
  	ret = __kvmppc_vcpu_run(kvm_run, vcpu);

  	/* No need for kvm_guest_exit. It's done in handle_exit.

diff --git a/arch/powerpc/kvm/e500.h b/arch/powerpc/kvm/e500.h
index 4fd9650..fc4b2f6 100644
--- a/arch/powerpc/kvm/e500.h
+++ b/arch/powerpc/kvm/e500.h

@@ -31,11 +31,13 @@ enum vcpu_ftr {
  #define E500_TLB_NUM   2

  /* entry is mapped somewhere in host TLB */
-#define E500_TLB_VALID		(1 << 0)
+#define E500_TLB_VALID		(1 << 31)
  /* TLB1 entry is mapped by host TLB1, tracked by bitmaps */
-#define E500_TLB_BITMAP		(1 << 1)
+#define E500_TLB_BITMAP		(1 << 30)
  /* TLB1 entry is mapped by host TLB0 */
-#define E500_TLB_TLB0		(1 << 2)
+#define E500_TLB_TLB0		(1 << 29)
+/* Lower 5 bits have WIMGE value */
+#define E500_TLB_WIMGE_MASK	(0x1f)

  struct tlbe_ref {
  	pfn_t pfn;		/* valid only for TLB0, except briefly */

diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index 1c6a9d7..9b10b0b 100644
--- a/arch/powerpc/kvm/e500_mmu_host.c
+++ b/arch/powerpc/kvm/e500_mmu_host.c

@@ -64,15 +64,6 @@ static inline u32 e500_shadow_mas3_attrib(u32 mas3, int usermode)
  	return mas3;
  }

-static inline u32 e500_shadow_mas2_attrib(u32 mas2, int usermode)
-{
-#ifdef CONFIG_SMP
-	return (mas2 & MAS2_ATTRIB_MASK) | MAS2_M;
-#else
-	return mas2 & MAS2_ATTRIB_MASK;
-#endif
-}
-
  /*
   * writing shadow tlb entry to host TLB
   */

@@ -248,10 +239,12 @@ 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,
-					 pfn_t pfn)
+					 pfn_t pfn, int wimg)
  {
  	ref->pfn = pfn;
  	ref->flags |= E500_TLB_VALID;
+	/* Use guest supplied MAS2_G and MAS2_E */
+	ref->flags |= (gtlbe->mas2 & MAS2_ATTRIB_MASK) | wimg;

  	if (tlbe_is_writable(gtlbe))
  		kvm_set_pfn_dirty(pfn);

@@ -312,8 +305,7 @@ static void kvmppc_e500_setup_stlbe(

  	/* Force IPROT=0 for all guest mappings. */
  	stlbe->mas1 = MAS1_TSIZE(tsize) | get_tlb_sts(gtlbe) | MAS1_VALID;
-	stlbe->mas2 = (gvaddr & MAS2_EPN) |
-		      e500_shadow_mas2_attrib(gtlbe->mas2, pr);
+	stlbe->mas2 = (gvaddr & MAS2_EPN) | (ref->flags & E500_TLB_WIMGE_MASK);
  	stlbe->mas7_3 = ((u64)pfn << PAGE_SHIFT) |
  			e500_shadow_mas3_attrib(gtlbe->mas7_3, pr);

@@ -332,6 +324,8 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
  	unsigned long hva;
  	int pfnmap = 0;
  	int tsize = BOOK3E_PAGESZ_4K;
+	pte_t pte;
+	int wimg = 0;

  	/*
  	 * Translate guest physical to true physical, acquiring

@@ -437,6 +431,8 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,

  	if (likely(!pfnmap)) {
  		unsigned long tsize_pages = 1 << (tsize + 10 - PAGE_SHIFT);
+		pgd_t *pgdir;
+
  		pfn = gfn_to_pfn_memslot(slot, gfn);
  		if (is_error_noslot_pfn(pfn)) {
  			printk(KERN_ERR "Couldn't get real page for gfn %lx!\n",

@@ -447,9 +443,18 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
  		/* Align guest and physical address to page map boundaries */
  		pfn &= ~(tsize_pages - 1);
  		gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1);
+		pgdir = vcpu_e500->vcpu.arch.pgdir;
+		pte = lookup_linux_pte(pgdir, hva, 1, &tsize_pages);
+		if (pte_present(pte)) {
+			wimg = (pte >> PTE_WIMGE_SHIFT) & MAS2_WIMGE_MASK;

+		} else {
+			printk(KERN_ERR "pte not present: gfn %lx, pfn %lx\n",
+					(long)gfn, pfn);
+			return -EINVAL;
+		}
  	}

-	kvmppc_e500_ref_setup(ref, gtlbe, pfn);
+	kvmppc_e500_ref_setup(ref, gtlbe, pfn, wimg);

  	kvmppc_e500_setup_stlbe(&vcpu_e500->vcpu, gtlbe, tsize,
  				ref, gvaddr, stlbe);