KVM: PPC: Book3S HV: Split HPT allocation from activation

Currently, kvmppc_alloc_hpt() both allocates a new hashed page table (HPT)
and sets it up as the active page table for a VM.  For the upcoming HPT
resize implementation we're going to want to allocate HPTs separately from
activating them.

So, split the allocation itself out into kvmppc_allocate_hpt() and perform
the activation with a new kvmppc_set_hpt() function.  Likewise we split
kvmppc_free_hpt(), which just frees the HPT, from kvmppc_release_hpt()
which unsets it as an active HPT, then frees it.

We also move the logic to fall back to smaller HPT sizes if the first try
fails into the single caller which used that behaviour,
kvmppc_hv_setup_htab_rma().  This introduces a slight semantic change, in
that previously if the initial attempt at CMA allocation failed, we would
fall back to attempting smaller sizes with the page allocator.  Now, we
try first CMA, then the page allocator at each size.  As far as I can tell
this change should be harmless.

To match, we make kvmppc_free_hpt() just free the actual HPT itself.  The
call to kvmppc_free_lpid() that was there, we move to the single caller.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

diff --git a/arch/powerpc/include/asm/kvm_book3s_64.h b/arch/powerpc/include/asm/kvm_book3s_64.h
index ecc3b33bcc59c0a4af1e8eb36f84d5bdd9906889..d9b48f5bb606a79259a6598380c874399e9def47 100644 (file)
--- a/arch/powerpc/include/asm/kvm_book3s_64.h
+++ b/arch/powerpc/include/asm/kvm_book3s_64.h
@@ -22,6 +22,10 @@
 
 #include <asm/book3s/64/mmu-hash.h>
 
+/* Power architecture requires HPT is at least 256kiB, at most 64TiB */
+#define PPC_MIN_HPT_ORDER      18
+#define PPC_MAX_HPT_ORDER      46
+
 #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE
 static inline struct kvmppc_book3s_shadow_vcpu *svcpu_get(struct kvm_vcpu *vcpu)
 {

diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 6fad1f12e9ec7c5c6ce426859ead8ade155d4407..ba61dec72089d609f59fa9671c579986d0cf773e 100644 (file)
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -155,9 +155,10 @@ extern void kvmppc_core_destroy_mmu(struct kvm_vcpu *vcpu);
 extern int kvmppc_kvm_pv(struct kvm_vcpu *vcpu);
 extern void kvmppc_map_magic(struct kvm_vcpu *vcpu);
 
-extern long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp);
+extern int kvmppc_allocate_hpt(struct kvm_hpt_info *info, u32 order);
+extern void kvmppc_set_hpt(struct kvm *kvm, struct kvm_hpt_info *info);
 extern long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp);
-extern void kvmppc_free_hpt(struct kvm *kvm);
+extern void kvmppc_free_hpt(struct kvm_hpt_info *info);
 extern long kvmppc_prepare_vrma(struct kvm *kvm,
                                struct kvm_userspace_memory_region *mem);
 extern void kvmppc_map_vrma(struct kvm_vcpu *vcpu,

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index d89995ef6c7ba40244551ffc2af3fe9e08602eb0..62d132a3cec5a5ccff831f71d4476b1f926a6e7d 100644 (file)
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -40,74 +40,66 @@
 
 #include "trace_hv.h"
 
-/* Power architecture requires HPT is at least 256kB */
-#define PPC_MIN_HPT_ORDER      18
-
 static long kvmppc_virtmode_do_h_enter(struct kvm *kvm, unsigned long flags,
                                long pte_index, unsigned long pteh,
                                unsigned long ptel, unsigned long *pte_idx_ret);
 static void kvmppc_rmap_reset(struct kvm *kvm);
 
-long kvmppc_alloc_hpt(struct kvm *kvm, u32 *htab_orderp)
+int kvmppc_allocate_hpt(struct kvm_hpt_info *info, u32 order)
 {
        unsigned long hpt = 0;
-       struct revmap_entry *rev;
+       int cma = 0;
        struct page *page = NULL;
-       long order = KVM_DEFAULT_HPT_ORDER;
+       struct revmap_entry *rev;
+       unsigned long npte;
 
-       if (htab_orderp) {
-               order = *htab_orderp;
-               if (order < PPC_MIN_HPT_ORDER)
-                       order = PPC_MIN_HPT_ORDER;
-       }
+       if ((order < PPC_MIN_HPT_ORDER) || (order > PPC_MAX_HPT_ORDER))
+               return -EINVAL;
 
-       kvm->arch.hpt.cma = 0;
        page = kvm_alloc_hpt_cma(1ul << (order - PAGE_SHIFT));
        if (page) {
                hpt = (unsigned long)pfn_to_kaddr(page_to_pfn(page));
                memset((void *)hpt, 0, (1ul << order));
-               kvm->arch.hpt.cma = 1;
+               cma = 1;
        }
 
-       /* Lastly try successively smaller sizes from the page allocator */
-       /* Only do this if userspace didn't specify a size via ioctl */
-       while (!hpt && order > PPC_MIN_HPT_ORDER && !htab_orderp) {
-               hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT|
-                                      __GFP_NOWARN, order - PAGE_SHIFT);
-               if (!hpt)
-                       --order;
-       }
+       if (!hpt)
+               hpt = __get_free_pages(GFP_KERNEL|__GFP_ZERO|__GFP_REPEAT
+                                      |__GFP_NOWARN, order - PAGE_SHIFT);
 
        if (!hpt)
                return -ENOMEM;
 
-       kvm->arch.hpt.virt = hpt;
-       kvm->arch.hpt.order = order;
-
-       atomic64_set(&kvm->arch.mmio_update, 0);
+       /* HPTEs are 2**4 bytes long */
+       npte = 1ul << (order - 4);
 
        /* Allocate reverse map array */
-       rev = vmalloc(sizeof(struct revmap_entry) * kvmppc_hpt_npte(&kvm->arch.hpt));
+       rev = vmalloc(sizeof(struct revmap_entry) * npte);
        if (!rev) {
-               pr_err("kvmppc_alloc_hpt: Couldn't alloc reverse map array\n");
-               goto out_freehpt;
+               pr_err("kvmppc_allocate_hpt: Couldn't alloc reverse map array\n");
+               if (cma)
+                       kvm_free_hpt_cma(page, 1 << (order - PAGE_SHIFT));
+               else
+                       free_pages(hpt, order - PAGE_SHIFT);
+               return -ENOMEM;
        }
-       kvm->arch.hpt.rev = rev;
-       kvm->arch.sdr1 = __pa(hpt) | (order - 18);
 
-       pr_info("KVM guest htab at %lx (order %ld), LPID %x\n",
-               hpt, order, kvm->arch.lpid);
+       info->order = order;
+       info->virt = hpt;
+       info->cma = cma;
+       info->rev = rev;
 
-       if (htab_orderp)
-               *htab_orderp = order;
        return 0;
+}
 
- out_freehpt:
-       if (kvm->arch.hpt.cma)
-               kvm_free_hpt_cma(page, 1 << (order - PAGE_SHIFT));
-       else
-               free_pages(hpt, order - PAGE_SHIFT);
-       return -ENOMEM;
+void kvmppc_set_hpt(struct kvm *kvm, struct kvm_hpt_info *info)
+{
+       atomic64_set(&kvm->arch.mmio_update, 0);
+       kvm->arch.hpt = *info;
+       kvm->arch.sdr1 = __pa(info->virt) | (info->order - 18);
+
+       pr_info("KVM guest htab at %lx (order %ld), LPID %x\n",
+               info->virt, (long)info->order, kvm->arch.lpid);
 }
 
 long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp)
@@ -141,23 +133,28 @@ long kvmppc_alloc_reset_hpt(struct kvm *kvm, u32 *htab_orderp)
                *htab_orderp = order;
                err = 0;
        } else {
-               err = kvmppc_alloc_hpt(kvm, htab_orderp);
-               order = *htab_orderp;
+               struct kvm_hpt_info info;
+
+               err = kvmppc_allocate_hpt(&info, *htab_orderp);
+               if (err < 0)
+                       goto out;
+               kvmppc_set_hpt(kvm, &info);
        }
  out:
        mutex_unlock(&kvm->lock);
        return err;
 }
 
-void kvmppc_free_hpt(struct kvm *kvm)
+void kvmppc_free_hpt(struct kvm_hpt_info *info)
 {
-       vfree(kvm->arch.hpt.rev);
-       if (kvm->arch.hpt.cma)
-               kvm_free_hpt_cma(virt_to_page(kvm->arch.hpt.virt),
-                                1 << (kvm->arch.hpt.order - PAGE_SHIFT));
-       else if (kvm->arch.hpt.virt)
-               free_pages(kvm->arch.hpt.virt,
-                          kvm->arch.hpt.order - PAGE_SHIFT);
+       vfree(info->rev);
+       if (info->cma)
+               kvm_free_hpt_cma(virt_to_page(info->virt),
+                                1 << (info->order - PAGE_SHIFT));
+       else if (info->virt)
+               free_pages(info->virt, info->order - PAGE_SHIFT);
+       info->virt = 0;
+       info->order = 0;
 }
 
 /* Bits in first HPTE dword for pagesize 4k, 64k or 16M */

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 02607128a4d4a0c17f7aa885e0a71d12b65a8452..19987e4343c3f9b12caf7e750a2455686cedbd34 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3198,11 +3198,22 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)
 
        /* Allocate hashed page table (if not done already) and reset it */
        if (!kvm->arch.hpt.virt) {
-               err = kvmppc_alloc_hpt(kvm, NULL);
-               if (err) {
+               int order = KVM_DEFAULT_HPT_ORDER;
+               struct kvm_hpt_info info;
+
+               err = kvmppc_allocate_hpt(&info, order);
+               /* If we get here, it means userspace didn't specify a
+                * size explicitly.  So, try successively smaller
+                * sizes if the default failed. */
+               while ((err == -ENOMEM) && --order >= PPC_MIN_HPT_ORDER)
+                       err  = kvmppc_allocate_hpt(&info, order);
+
+               if (err < 0) {
                        pr_err("KVM: Couldn't alloc HPT\n");
                        goto out;
                }
+
+               kvmppc_set_hpt(kvm, &info);
        }
 
        /* Look up the memslot for guest physical address 0 */
@@ -3467,7 +3478,7 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
        if (kvm_is_radix(kvm))
                kvmppc_free_radix(kvm);
        else
-               kvmppc_free_hpt(kvm);
+               kvmppc_free_hpt(&kvm->arch.hpt);
 
        kvmppc_free_pimap(kvm);
 }