diff mbox

[6/6,v3] kvm: powerpc: use caching attributes as per linux pte

Message ID 1375788674-13140-7-git-send-email-Bharat.Bhushan@freescale.com
State New, archived
Headers show

Commit Message

Bharat Bhushan Aug. 6, 2013, 11:31 a.m. UTC 
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 <bharat.bhushan@freescale.com>
---
v2->v3
 - setting pgdir before kvmppc_fix_ee_before_entry() on vcpu_run
 - Aligned as per changes in patch 5/6
 - setting WIMG for pfnmap pages also
 
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    |   36 ++++++++++++++++++++--------------
 4 files changed, 28 insertions(+), 20 deletions(-)

Comments

Scott Wood Aug. 10, 2013, 1:04 a.m. UTC | #1 
On Tue, 2013-08-06 at 17:01 +0530, Bharat Bhushan wrote:
> @@ -449,7 +446,16 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
>  		gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1);
>  	}
>  
> -	kvmppc_e500_ref_setup(ref, gtlbe, pfn);
> +	pgdir = vcpu_e500->vcpu.arch.pgdir;
> +	ptep = lookup_linux_pte(pgdir, hva, &tsize_pages);
> +	if (pte_present(*ptep)) {
> +		wimg = (pte_val(*ptep) >> PTE_WIMGE_SHIFT) & MAS2_WIMGE_MASK;
> +	} else {
> +		printk(KERN_ERR "pte not present: gfn %lx, pfn %lx\n",
> +				(long)gfn, pfn);
> +		return -EINVAL;

Don't let the guest spam the host kernel console by repeatedly accessing
bad mappings (even if it requires host userspace to assist by pointing a
memslot at a bad hva).  This should at most be printk_ratelimited(), and
probably just pr_debug().  It should also have __func__ context.

Also, I don't see the return value getting checked (the immediate
callers check it and propogate the error, but kvmppc_mmu_map() doesn't).
We want to send a machine check to the guest if this happens (or
possibly exit to userspace since it indicates a bad memslot, not just a
guest bug).  We don't want to just silently retry over and over.

Otherwise, this series looks good to me.

-Scott



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diff mbox

Patch

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..0d96d50 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -696,8 +696,8 @@  int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
 	kvmppc_load_guest_fp(vcpu);
 #endif
 
+	vcpu->arch.pgdir = current->mm->pgd;
 	kvmppc_fix_ee_before_entry();
-
 	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..001a2b0 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 +324,10 @@  static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 	unsigned long hva;
 	int pfnmap = 0;
 	int tsize = BOOK3E_PAGESZ_4K;
+	unsigned long tsize_pages = 0;
+	pte_t *ptep;
+	int wimg = 0;
+	pgd_t *pgdir;
 
 	/*
 	 * Translate guest physical to true physical, acquiring
@@ -394,7 +390,7 @@  static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 			 */
 
 			for (; tsize > BOOK3E_PAGESZ_4K; tsize -= 2) {
-				unsigned long gfn_start, gfn_end, tsize_pages;
+				unsigned long gfn_start, gfn_end;
 				tsize_pages = 1 << (tsize - 2);
 
 				gfn_start = gfn & ~(tsize_pages - 1);
@@ -436,7 +432,8 @@  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);
+		tsize_pages = 1 << (tsize + 10 - PAGE_SHIFT);
+
 		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",
@@ -449,7 +446,16 @@  static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
 		gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1);
 	}
 
-	kvmppc_e500_ref_setup(ref, gtlbe, pfn);
+	pgdir = vcpu_e500->vcpu.arch.pgdir;
+	ptep = lookup_linux_pte(pgdir, hva, &tsize_pages);
+	if (pte_present(*ptep)) {
+		wimg = (pte_val(*ptep) >> 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, wimg);
 
 	kvmppc_e500_setup_stlbe(&vcpu_e500->vcpu, gtlbe, tsize,
 				ref, gvaddr, stlbe);