Implement a real mode handler for the H_CALL H_PAGE_INIT which can be
used to zero or copy a guest page. The page is defined to be 4k and must
be 4k aligned.
The in-kernel real mode handler halves the time to handle this H_CALL
compared to handling it in userspace for a hash guest.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@xxxxxxxxx>
---
arch/powerpc/include/asm/kvm_ppc.h | 2 +
arch/powerpc/kvm/book3s_hv_rm_mmu.c | 144 ++++++++++++++++++++++++++++++++
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 2 +-
3 files changed, 147 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index 8e8bb1299a0e..f34f290463aa 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -653,6 +653,8 @@ long kvmppc_h_clear_ref(struct kvm_vcpu *vcpu, unsigned long flags,
unsigned long pte_index);
long kvmppc_h_clear_mod(struct kvm_vcpu *vcpu, unsigned long flags,
unsigned long pte_index);
+long kvmppc_rm_h_page_init(struct kvm_vcpu *vcpu, unsigned long flags,
+ unsigned long dest, unsigned long src);
long kvmppc_hpte_hv_fault(struct kvm_vcpu *vcpu, unsigned long addr,
unsigned long slb_v, unsigned int status, bool data);
unsigned long kvmppc_rm_h_xirr(struct kvm_vcpu *vcpu);
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 3b3791ed74a6..26cfe1480ff5 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -867,6 +867,150 @@ long kvmppc_h_clear_mod(struct kvm_vcpu *vcpu, unsigned long flags,
return ret;
}
+static int kvmppc_get_hpa(struct kvm_vcpu *vcpu, unsigned long gpa,
+ int writing, unsigned long *hpa,
+ struct kvm_memory_slot **memslot_p)
+{
+ struct kvm *kvm = vcpu->kvm;
+ struct kvm_memory_slot *memslot;
+ unsigned long gfn, hva, pa, psize = PAGE_SHIFT;
+ unsigned int shift;
+ pte_t *ptep, pte;
+
+ /* Find the memslot for this address */
+ gfn = gpa >> PAGE_SHIFT;
+ memslot = __gfn_to_memslot(kvm_memslots_raw(kvm), gfn);
+ if (!memslot || (memslot->flags & KVM_MEMSLOT_INVALID))
+ return H_PARAMETER;
+
+ /* Translate to host virtual address */
+ hva = __gfn_to_hva_memslot(memslot, gfn);
+
+ /* Try to find the host pte for that virtual address */
+ ptep = __find_linux_pte(vcpu->arch.pgdir, hva, NULL, &shift);
+ if (!ptep)
+ return H_TOO_HARD;
+ pte = kvmppc_read_update_linux_pte(ptep, writing);
+ if (!pte_present(pte))
+ return H_TOO_HARD;
+
+ /* Convert to a physical address */
+ if (shift)
+ psize = 1UL << shift;
+ pa = pte_pfn(pte) << PAGE_SHIFT;
+ pa |= hva & (psize - 1);
+ pa |= gpa & ~PAGE_MASK;
+
+ if (hpa)
+ *hpa = pa;
+ if (memslot_p)
+ *memslot_p = memslot;
+
+ return H_SUCCESS;
+}
+
+static int kvmppc_do_h_page_init_zero(struct kvm_vcpu *vcpu, unsigned long dest)
+{
+ struct kvm *kvm = vcpu->kvm;
+ struct kvm_memory_slot *memslot;
+ unsigned long pa;
+ unsigned long mmu_seq;
+ int i, ret = H_SUCCESS;
+
+ /* Used later to detect if we might have been invalidated */
+ mmu_seq = kvm->mmu_notifier_seq;
+ smp_rmb();
+
+ ret = kvmppc_get_hpa(vcpu, dest, 1, &pa, &memslot);
+ if (ret != H_SUCCESS)
+ return ret;
+
+ /* Check if we've been invalidated */
+ spin_lock(&kvm->mmu_lock);
+ if (mmu_notifier_retry(kvm, mmu_seq)) {
+ ret = H_TOO_HARD;
+ goto out_unlock;
+ }
+
+ /* Zero the page */
+ for (i = 0; i < 4096; i += L1_CACHE_BYTES, pa += L1_CACHE_BYTES)
+ dcbz((void *)pa);
+ kvmppc_update_dirty_map(memslot, dest >> PAGE_SHIFT, PAGE_SIZE);
+
+out_unlock:
+ spin_unlock(&kvm->mmu_lock);
+ return ret;
+}
+
+static int kvmppc_do_h_page_init_copy(struct kvm_vcpu *vcpu, unsigned long dest,
+ unsigned long src)
+{
+ struct kvm *kvm = vcpu->kvm;
+ struct kvm_memory_slot *dest_memslot;
+ unsigned long dest_pa, src_pa;
+ unsigned long mmu_seq;
+ int ret = H_SUCCESS;
+
+ /* Used later to detect if we might have been invalidated */
+ mmu_seq = kvm->mmu_notifier_seq;
+ smp_rmb();
+
+ ret = kvmppc_get_hpa(vcpu, dest, 1, &dest_pa, &dest_memslot);
+ if (ret != H_SUCCESS)
+ return ret;
+ ret = kvmppc_get_hpa(vcpu, src, 0, &src_pa, NULL);
+ if (ret != H_SUCCESS)
+ return ret;
+
+ /* Check if we've been invalidated */
+ spin_lock(&kvm->mmu_lock);
+ if (mmu_notifier_retry(kvm, mmu_seq)) {
+ ret = H_TOO_HARD;
+ goto out_unlock;
+ }
+
+ /* Copy the page */
+ memcpy((void *)dest_pa, (void *)src_pa, 4096);
+
+ kvmppc_update_dirty_map(dest_memslot, dest >> PAGE_SHIFT, PAGE_SIZE);
+
+out_unlock:
+ spin_unlock(&kvm->mmu_lock);
+ return ret;
+}
+
+long kvmppc_rm_h_page_init(struct kvm_vcpu *vcpu, unsigned long flags,
+ unsigned long dest, unsigned long src)
+{
+ struct kvm *kvm = vcpu->kvm;
+ u64 pg_sz = 1UL << 12; /* 4K page size */
+ u64 pg_mask = pg_sz - 1;
+ int ret = H_SUCCESS;
+
+ /* Don't handle radix mode here, go up to the virtual mode handler */
+ if (kvm_is_radix(kvm))
+ return H_TOO_HARD;
+
+ /* Check for invalid flags (H_PAGE_SET_LOANED covers all CMO flags) */
+ if (flags & ~(H_ICACHE_INVALIDATE | H_ICACHE_SYNCHRONIZE |
+ H_ZERO_PAGE | H_COPY_PAGE | H_PAGE_SET_LOANED))
+ return H_PARAMETER;
+
+ /* dest (and src if copy_page flag set) must be page aligned */
+ if ((dest & pg_mask) || ((flags & H_COPY_PAGE) && (src & pg_mask)))
+ return H_PARAMETER;
+
+ /* zero and/or copy the page as determined by the flags */
+ if (flags & H_ZERO_PAGE)
+ ret = kvmppc_do_h_page_init_zero(vcpu, dest);
+ if (flags & H_COPY_PAGE)
+ ret = kvmppc_do_h_page_init_copy(vcpu, dest, src);
+
+ /* We can ignore the other flags */
+
+ return ret;
+}
+
void kvmppc_invalidate_hpte(struct kvm *kvm, __be64 *hptep,
unsigned long pte_index)
{
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 9b8d50a7cbaf..5927497e7bbf 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -2268,7 +2268,7 @@ hcall_real_table:
.long DOTSYM(kvmppc_rm_h_put_tce) - hcall_real_table
.long 0 /* 0x24 - H_SET_SPRG0 */
.long DOTSYM(kvmppc_h_set_dabr) - hcall_real_table
- .long 0 /* 0x2c */
+ .long DOTSYM(kvmppc_rm_h_page_init) - hcall_real_table
.long 0 /* 0x30 */
.long 0 /* 0x34 */
.long 0 /* 0x38 */
--
2.13.6
