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SubjectRe: [PATCH v5 1/4] nitro_enclaves: Merge contiguous physical memory regions
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On 07/11/2021 16:09, Longpeng(Mike) wrote:
>
> From: Longpeng <longpeng2@huawei.com>
>
> There can be cases when there are more memory regions that need to be
> set for an enclave than the maximum supported number of memory regions
> per enclave. One example can be when the memory regions are backed by 2
> MiB hugepages (the minimum supported hugepage size).
>
> Let's merge the adjacent regions if they are physically contiguous. This
> way the final number of memory regions is less than before merging and
> could potentially avoid reaching maximum.
>
> Signed-off-by: Longpeng <longpeng2@huawei.com>
> ---
> Changes v4 -> v5:
> - "Physical contiguous memory regions" -> "Contiguous physical memory
> regions." [Andra]
> - fix the warning of aligment that reported by the checkpath.pl [Andra]
>
> Changes v3 -> v4:
> - move "#include <linux/range.h>" according to the alphabetical order. [Andra]
> - rename several variables, parameters, structures and functions. [Andra]
> - add missing "Context" in the comments. [Andra]
> - some other changes to makes the code much neater. [Andra]
>
> Changes v2 -> v3:
> - update the commit title and commit message. [Andra]
> - use 'struct range' to instead of 'struct phys_mem_region'. [Andra, Greg KH]
> - add comments before the function definition. [Andra]
> - rename several variables, parameters and function. [Andra]
> ---
> drivers/virt/nitro_enclaves/ne_misc_dev.c | 84 ++++++++++++++++++++-----------
> 1 file changed, 56 insertions(+), 28 deletions(-)
>

Reviewed-by: Andra Paraschiv <andraprs@amazon.com>

Thanks,
Andra

> diff --git a/drivers/virt/nitro_enclaves/ne_misc_dev.c b/drivers/virt/nitro_enclaves/ne_misc_dev.c
> index 8939612..ced58de 100644
> --- a/drivers/virt/nitro_enclaves/ne_misc_dev.c
> +++ b/drivers/virt/nitro_enclaves/ne_misc_dev.c
> @@ -24,6 +24,7 @@
> #include <linux/nitro_enclaves.h>
> #include <linux/pci.h>
> #include <linux/poll.h>
> +#include <linux/range.h>
> #include <linux/slab.h>
> #include <linux/types.h>
> #include <uapi/linux/vm_sockets.h>
> @@ -126,6 +127,16 @@ struct ne_cpu_pool {
> static struct ne_cpu_pool ne_cpu_pool;
>
> /**
> + * struct ne_phys_contig_mem_regions - Contiguous physical memory regions.
> + * @num: The number of regions that currently has.
> + * @regions: The array of physical memory regions.
> + */
> +struct ne_phys_contig_mem_regions {
> + unsigned long num;
> + struct range *regions;
> +};
> +
> +/**
> * ne_check_enclaves_created() - Verify if at least one enclave has been created.
> * @void: No parameters provided.
> *
> @@ -825,6 +836,33 @@ static int ne_sanity_check_user_mem_region_page(struct ne_enclave *ne_enclave,
> }
>
> /**
> + * ne_merge_phys_contig_memory_regions() - Add a memory region and merge the adjacent
> + * regions if they are physically contiguous.
> + * @phys_contig_regions : Private data associated with the contiguous physical memory regions.
> + * @page_paddr : Physical start address of the region to be added.
> + * @page_size : Length of the region to be added.
> + *
> + * Context: Process context. This function is called with the ne_enclave mutex held.
> + */
> +static void
> +ne_merge_phys_contig_memory_regions(struct ne_phys_contig_mem_regions *phys_contig_regions,
> + u64 page_paddr, u64 page_size)
> +{
> + unsigned long num = phys_contig_regions->num;
> +
> + /* Physically contiguous, just merge */
> + if (num && (phys_contig_regions->regions[num - 1].end + 1) == page_paddr) {
> + phys_contig_regions->regions[num - 1].end += page_size;
> +
> + return;
> + }
> +
> + phys_contig_regions->regions[num].start = page_paddr;
> + phys_contig_regions->regions[num].end = page_paddr + page_size - 1;
> + phys_contig_regions->num++;
> +}
> +
> +/**
> * ne_set_user_memory_region_ioctl() - Add user space memory region to the slot
> * associated with the current enclave.
> * @ne_enclave : Private data associated with the current enclave.
> @@ -843,9 +881,8 @@ static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
> unsigned long max_nr_pages = 0;
> unsigned long memory_size = 0;
> struct ne_mem_region *ne_mem_region = NULL;
> - unsigned long nr_phys_contig_mem_regions = 0;
> struct pci_dev *pdev = ne_devs.ne_pci_dev->pdev;
> - struct page **phys_contig_mem_regions = NULL;
> + struct ne_phys_contig_mem_regions phys_contig_mem_regions = {};
> int rc = -EINVAL;
>
> rc = ne_sanity_check_user_mem_region(ne_enclave, mem_region);
> @@ -866,9 +903,10 @@ static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
> goto free_mem_region;
> }
>
> - phys_contig_mem_regions = kcalloc(max_nr_pages, sizeof(*phys_contig_mem_regions),
> - GFP_KERNEL);
> - if (!phys_contig_mem_regions) {
> + phys_contig_mem_regions.regions = kcalloc(max_nr_pages,
> + sizeof(*phys_contig_mem_regions.regions),
> + GFP_KERNEL);
> + if (!phys_contig_mem_regions.regions) {
> rc = -ENOMEM;
>
> goto free_mem_region;
> @@ -901,26 +939,16 @@ static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
> if (rc < 0)
> goto put_pages;
>
> - /*
> - * TODO: Update once handled non-contiguous memory regions
> - * received from user space or contiguous physical memory regions
> - * larger than 2 MiB e.g. 8 MiB.
> - */
> - phys_contig_mem_regions[i] = ne_mem_region->pages[i];
> + ne_merge_phys_contig_memory_regions(&phys_contig_mem_regions,
> + page_to_phys(ne_mem_region->pages[i]),
> + page_size(ne_mem_region->pages[i]));
>
> memory_size += page_size(ne_mem_region->pages[i]);
>
> ne_mem_region->nr_pages++;
> } while (memory_size < mem_region.memory_size);
>
> - /*
> - * TODO: Update once handled non-contiguous memory regions received
> - * from user space or contiguous physical memory regions larger than
> - * 2 MiB e.g. 8 MiB.
> - */
> - nr_phys_contig_mem_regions = ne_mem_region->nr_pages;
> -
> - if ((ne_enclave->nr_mem_regions + nr_phys_contig_mem_regions) >
> + if ((ne_enclave->nr_mem_regions + phys_contig_mem_regions.num) >
> ne_enclave->max_mem_regions) {
> dev_err_ratelimited(ne_misc_dev.this_device,
> "Reached max memory regions %lld\n",
> @@ -931,9 +959,9 @@ static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
> goto put_pages;
> }
>
> - for (i = 0; i < nr_phys_contig_mem_regions; i++) {
> - u64 phys_region_addr = page_to_phys(phys_contig_mem_regions[i]);
> - u64 phys_region_size = page_size(phys_contig_mem_regions[i]);
> + for (i = 0; i < phys_contig_mem_regions.num; i++) {
> + u64 phys_region_addr = phys_contig_mem_regions.regions[i].start;
> + u64 phys_region_size = range_len(&phys_contig_mem_regions.regions[i]);
>
> if (phys_region_size & (NE_MIN_MEM_REGION_SIZE - 1)) {
> dev_err_ratelimited(ne_misc_dev.this_device,
> @@ -959,13 +987,13 @@ static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
>
> list_add(&ne_mem_region->mem_region_list_entry, &ne_enclave->mem_regions_list);
>
> - for (i = 0; i < nr_phys_contig_mem_regions; i++) {
> + for (i = 0; i < phys_contig_mem_regions.num; i++) {
> struct ne_pci_dev_cmd_reply cmd_reply = {};
> struct slot_add_mem_req slot_add_mem_req = {};
>
> slot_add_mem_req.slot_uid = ne_enclave->slot_uid;
> - slot_add_mem_req.paddr = page_to_phys(phys_contig_mem_regions[i]);
> - slot_add_mem_req.size = page_size(phys_contig_mem_regions[i]);
> + slot_add_mem_req.paddr = phys_contig_mem_regions.regions[i].start;
> + slot_add_mem_req.size = range_len(&phys_contig_mem_regions.regions[i]);
>
> rc = ne_do_request(pdev, SLOT_ADD_MEM,
> &slot_add_mem_req, sizeof(slot_add_mem_req),
> @@ -974,7 +1002,7 @@ static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
> dev_err_ratelimited(ne_misc_dev.this_device,
> "Error in slot add mem [rc=%d]\n", rc);
>
> - kfree(phys_contig_mem_regions);
> + kfree(phys_contig_mem_regions.regions);
>
> /*
> * Exit here without put pages as memory regions may
> @@ -987,7 +1015,7 @@ static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
> ne_enclave->nr_mem_regions++;
> }
>
> - kfree(phys_contig_mem_regions);
> + kfree(phys_contig_mem_regions.regions);
>
> return 0;
>
> @@ -995,7 +1023,7 @@ static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
> for (i = 0; i < ne_mem_region->nr_pages; i++)
> put_page(ne_mem_region->pages[i]);
> free_mem_region:
> - kfree(phys_contig_mem_regions);
> + kfree(phys_contig_mem_regions.regions);
> kfree(ne_mem_region->pages);
> kfree(ne_mem_region);
>
> --
> 1.8.3.1
>



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