Tianyu Lan writes:
> From: Tianyu Lan
>
> Add new hvcall guest address host visibility support. Mark vmbus
> ring buffer visible to host when create gpadl buffer and mark back
> to not visible when tear down gpadl buffer.
>
> Co-developed-by: Sunil Muthuswamy
> Signed-off-by: Tianyu Lan
> ---
> arch/x86/hyperv/Makefile | 2 +-
> arch/x86/hyperv/ivm.c | 106 +
> arch/x86/include/asm/hyperv-tlfs.h | 24 +++
> arch/x86/include/asm/mshyperv.h| 4 +-
> arch/x86/mm/pat/set_memory.c | 10 ++-
> drivers/hv/channel.c | 38 ++-
> include/asm-generic/hyperv-tlfs.h | 1 +
> include/linux/hyperv.h | 10 +++
> 8 files changed, 190 insertions(+), 5 deletions(-)
> create mode 100644 arch/x86/hyperv/ivm.c
>
> diff --git a/arch/x86/hyperv/Makefile b/arch/x86/hyperv/Makefile
> index 48e2c51464e8..5d2de10809ae 100644
> --- a/arch/x86/hyperv/Makefile
> +++ b/arch/x86/hyperv/Makefile
> @@ -1,5 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0-only
> -obj-y:= hv_init.o mmu.o nested.o irqdomain.o
> +obj-y:= hv_init.o mmu.o nested.o irqdomain.o ivm.o
> obj-$(CONFIG_X86_64) += hv_apic.o hv_proc.o
>
> ifdef CONFIG_X86_64
> diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
> new file mode 100644
> index ..fad1d3024056
> --- /dev/null
> +++ b/arch/x86/hyperv/ivm.c
> @@ -0,0 +1,106 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Hyper-V Isolation VM interface with paravisor and hypervisor
> + *
> + * Author:
> + * Tianyu Lan
> + */
> +
> +#include
> +#include
> +#include
> +#include
> +#include
> +
> +/*
> + * hv_mark_gpa_visibility - Set pages visible to host via hvcall.
> + *
> + * In Isolation VM, all guest memory is encripted from host and guest
> + * needs to set memory visible to host via hvcall before sharing memory
> + * with host.
> + */
> +int hv_mark_gpa_visibility(u16 count, const u64 pfn[], u32 visibility)
> +{
> + struct hv_gpa_range_for_visibility **input_pcpu, *input;
> + u16 pages_processed;
> + u64 hv_status;
> + unsigned long flags;
> +
> + /* no-op if partition isolation is not enabled */
> + if (!hv_is_isolation_supported())
> + return 0;
> +
> + if (count > HV_MAX_MODIFY_GPA_REP_COUNT) {
> + pr_err("Hyper-V: GPA count:%d exceeds supported:%lu\n", count,
> + HV_MAX_MODIFY_GPA_REP_COUNT);
> + return -EINVAL;
> + }
> +
> + local_irq_save(flags);
> + input_pcpu = (struct hv_gpa_range_for_visibility **)
> + this_cpu_ptr(hyperv_pcpu_input_arg);
> + input = *input_pcpu;
> + if (unlikely(!input)) {
> + local_irq_restore(flags);
> + return -EINVAL;
> + }
> +
> + input->partition_id = HV_PARTITION_ID_SELF;
> + input->host_visibility = visibility;
> + input->reserved0 = 0;
> + input->reserved1 = 0;
> + memcpy((void *)input->gpa_page_list, pfn, count * sizeof(*pfn));
> + hv_status = hv_do_rep_hypercall(
> + HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY, count,
> + 0, input, _processed);
> + local_irq_restore(flags);
> +
> + if (!(hv_status & HV_HYPERCALL_RESULT_MASK))
> + return 0;
> +
> + return hv_status & HV_HYPERCALL_RESULT_MASK;
> +}
> +EXPORT_SYMBOL(hv_mark_gpa_visibility);
> +
> +/*
> + * hv_set_mem_host_visibility - Set specified memory visible to host.
> + *
> + * In Isolation VM, all guest memory is encrypted from host and guest
> + * needs to set memory visible to host via hvcall before sharing memory
> + * with host. This function works as wrap of hv_mark_gpa_visibility()
> + * with memory base and size.
> + */
> +int hv_set_mem_host_visibility(void *kbuffer, size_t size,
> +enum vmbus_page_visibility visibility)
> +{
> + int pagecount = size >> HV_HYP_PAGE_SHIFT;
> + u64 *pfn_array;
> + int ret = 0;
> + int i, pfn;
> +
> + if (!hv_is_isolation_supported())
> + return 0;
> +
> + pfn_array = vzalloc(HV_HYP_PAGE_SIZE);
> + if (!pfn_array)
> + return -ENOMEM;
> +
> + for (i = 0, pfn = 0; i < pagecount; i++) {
> + pfn_array[pfn] = virt_to_hvpfn(kbuffer + i * HV_HYP_PAGE_SIZE);
> + pfn++;
> +
> + if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
> + ret |= hv_mark_gpa_visibility(pfn, pfn_array,
> visibility);
> + pfn = 0;
> +
> + if (ret)
> + goto err_free_pfn_array;
> + }
> + }
> +
> + err_free_pfn_array:
> + vfree(pfn_array);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(hv_set_mem_host_visibility);
> +
> diff --git a/arch/x86/include/asm/hyperv-tlfs.h
> b/arch/x86/include/asm/hyperv-tlfs.h
> index 606f5cc579b2..632281b91b44 100644
> ---
