From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suraj Jitindar Singh Date: Tue, 19 Mar 2019 04:04:33 +0000 Subject: [PATCH 1/3] KVM: PPC: Implement kvmppc_copy_guest() to perform in place copy of guest memory Message-Id: <20190319040435.10716-1-sjitindarsingh@gmail.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm-ppc@vger.kernel.org Implement the function kvmppc_copy_guest() to be used to perform a memory copy from one guest physical address to another of a variable length. This performs similar functionality as the kvm_read_guest() and kvm_write_guest() functions, except both addresses point to guest memory. This performs a copy in place using raw_copy_in_user() to avoid having to buffer the data. The guest memory can reside in different memslots and the copy length can span memslots. Signed-off-by: Suraj Jitindar Singh --- arch/powerpc/kvm/book3s_hv.c | 69 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index ec38576dc685..7179ea783f4f 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -814,6 +814,75 @@ static int kvmppc_h_set_mode(struct kvm_vcpu *vcpu, unsigned long mflags, } } +static int __kvmppc_copy_guest_page(struct kvm_memory_slot *to_memslot, + gfn_t to_gfn, int to_offset, + struct kvm_memory_slot *from_memslot, + gfn_t from_gfn, int from_offset, int len) +{ + int r; + unsigned long to_addr, from_addr; + + to_addr = gfn_to_hva_memslot(to_memslot, to_gfn); + if (kvm_is_error_hva(to_addr)) + return -EFAULT; + from_addr = gfn_to_hva_memslot(from_memslot, from_gfn); + if (kvm_is_error_hva(from_addr)) + return -EFAULT; + r = raw_copy_in_user((void __user *)to_addr + to_offset, + (void __user *)from_addr + from_offset, len); + if (r) + return -EFAULT; + return 0; +} + +static int next_segment_many(unsigned long len, int offset1, int offset2) +{ + int size = min(PAGE_SIZE - offset1, PAGE_SIZE - offset2); + + if (len > size) + return size; + else + return len; +} + +static int kvmppc_copy_guest(struct kvm *kvm, gpa_t to, gpa_t from, + unsigned long len) +{ + struct kvm_memory_slot *to_memslot = NULL; + struct kvm_memory_slot *from_memslot = NULL; + gfn_t to_gfn = to >> PAGE_SHIFT; + gfn_t from_gfn = from >> PAGE_SHIFT; + int seg; + int to_offset = offset_in_page(to); + int from_offset = offset_in_page(from); + int ret; + + while ((seg = next_segment_many(len, to_offset, from_offset)) != 0) { + if (!to_memslot || (to_gfn >= (to_memslot->base_gfn + + to_memslot->npages))) + to_memslot = gfn_to_memslot(kvm, to_gfn); + if (!from_memslot || (from_gfn >= (from_memslot->base_gfn + + from_memslot->npages))) + from_memslot = gfn_to_memslot(kvm, from_gfn); + + ret = __kvmppc_copy_guest_page(to_memslot, to_gfn, to_offset, + from_memslot, from_gfn, + from_offset, seg); + if (ret < 0) + return ret; + mark_page_dirty(kvm, to_gfn); + + to_offset = (to_offset + seg) & (PAGE_SIZE - 1); + from_offset = (from_offset + seg) & (PAGE_SIZE - 1); + len -= seg; + if (!to_offset) + to_gfn += 1; + if (!from_offset) + from_gfn += 1; + } + return 0; +} + static int kvm_arch_vcpu_yield_to(struct kvm_vcpu *target) { struct kvmppc_vcore *vcore = target->arch.vcore; -- 2.13.6