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Date: Fri, 15 Oct 2021 16:33:32 +0300
From: "Paraschiv, Andra-Irina" <andraprs@...zon.com>
To: "Longpeng(Mike)" <longpeng2@...wei.com>
CC: <arei.gonglei@...wei.com>, <gregkh@...uxfoundation.org>,
<kamal@...onical.com>, <pbonzini@...hat.com>,
<sgarzare@...hat.com>, <stefanha@...hat.com>,
<vkuznets@...hat.com>, <linux-kernel@...r.kernel.org>,
<ne-devel-upstream@...zon.com>, <lexnv@...zon.com>,
<alcioa@...zon.com>
Subject: Re: [PATCH v3 1/4] nitro_enclaves: Merge contiguous physical memory
regions
On 09/10/2021 04:32, Longpeng(Mike) wrote:
>
> From: Longpeng <longpeng2@...wei.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 physical contiguous. This
physical contiguous => physically contiguous
> way the final number of memory regions is less than before merging and
> could potentially avoid reaching maximum.
>
> Signed-off-by: Longpeng <longpeng2@...wei.com>
> ---
> 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 | 79 +++++++++++++++++++++----------
> 1 file changed, 55 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/virt/nitro_enclaves/ne_misc_dev.c b/drivers/virt/nitro_enclaves/ne_misc_dev.c
> index e21e1e8..eea53e9 100644
> --- a/drivers/virt/nitro_enclaves/ne_misc_dev.c
> +++ b/drivers/virt/nitro_enclaves/ne_misc_dev.c
> @@ -26,6 +26,7 @@
> #include <linux/poll.h>
> #include <linux/slab.h>
> #include <linux/types.h>
> +#include <linux/range.h>
Please keep the alphabetical order and move this before "#include
<linux/slab.h>."
> #include <uapi/linux/vm_sockets.h>
>
> #include "ne_misc_dev.h"
> @@ -126,6 +127,16 @@ struct ne_cpu_pool {
> static struct ne_cpu_pool ne_cpu_pool;
>
> /**
> + * struct phys_contig_mem_regions - Physical contiguous memory regions
Physical contiguous memory regions => Contiguous physical memory regions
> + * @num: The number of regions that currently has.
> + * @region: The array of physical memory regions.
> + */
> +struct phys_contig_mem_regions {
> + unsigned long num;
> + struct range region[0];
Should use "struct range *regions" instead, to keep a similar style with
regard to arrays throughout the code.
Please align the fields name (e.g. [1]) so that it's easier to
distinguish between fields type and name.
Let's also prefix with "ne" the data structure naming e.g.
ne_phys_contig_mem_regions. So that is similar to other data structures
defined in the NE kernel driver codebase.
[1]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/virt/nitro_enclaves/ne_misc_dev.c#n118
> +};
> +
> +/**
> * 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 physical contiguous.
physical contiguous => physically contiguous
> + * @regions : Private data associated with the physical contiguous memory regions.
physical contiguous memory regions => contiguous physical memory regions
@regions => @phys_contig_regions
> + * @page_paddr: Physical start address of the region to be added.
> + * @page_size : Length of the region to be added.
> + *
> + * Return:
> + * * No return value.
Please add "Context: Process context. This function is called with the
ne_enclave mutex held." before "Return", similar to other defined functions.
Can remove these lines, as for now there is no return value:
* Return:
* * No return value.
And then can add this in the second patch in the series:
* Context: Process context. This function is called with the ne_enclave
mutex held. (note: already available in the first patch)
* Return: (note: added in the second patch)
* * 0 ...
> + */
> +static void
> +ne_merge_phys_contig_memory_regions(struct phys_contig_mem_regions *regions,
> + u64 page_paddr, u64 page_size)
phys_contig_mem_regions => ne_phys_contig_mem_regions
*regions => *phys_contig_regions
Can define something like this:
unsigned long num = phys_contig_regions->num;
and then use it inside the function, except the last line that
increments the num.
> +{
> + /* Physical contiguous, just merge */
Physical contiguous => Physically contiguous
> + if (regions->num &&
> + (regions->region[regions->num - 1].end + 1) == page_paddr) {
e.g. phys_contig_regions->regions[num - 1]
> + regions->region[regions->num - 1].end += page_size;
> +
> + return;
> + }
> +
> + regions->region[regions->num].start = page_paddr;
> + regions->region[regions->num].end = page_paddr + page_size - 1;
> + 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 +881,9 @@ 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 phys_contig_mem_regions *phys_contig_mem_regions = NULL;
struct phys_contig_mem_regions *phys_contig_mem_regions = NULL; =>
struct ne_phys_contig_mem_regions phys_contig_mem_regions = {};
> + size_t size_to_alloc = 0;
> int rc = -EINVAL;
>
> rc = ne_sanity_check_user_mem_region(ne_enclave, mem_region);
> @@ -866,8 +904,9 @@ 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);
> + size_to_alloc = sizeof(*phys_contig_mem_regions) +
> + max_nr_pages * sizeof(struct range);
> + phys_contig_mem_regions = kzalloc(size_to_alloc, GFP_KERNEL);
Then can alloc memory for the regions field.
phys_contig_mem_regions.regions = kcalloc(max_nr_pages,
sizeof(*phys_contig_mem_regions.regions), GFP_KERNEL);
The "size_of_alloc" will not be needed in this case.
> if (!phys_contig_mem_regions) {
> rc = -ENOMEM;
>
> @@ -901,26 +940,16 @@ 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,
And can pass it here like this: &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 +960,10 @@ 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++) {
> + struct range *range = phys_contig_mem_regions->region + i;
> + u64 phys_region_addr = range->start;
> + u64 phys_region_size = range_len(range);
With the updated data structure field, could be:
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 +989,14 @@ 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 = {};
> + struct range *range = phys_contig_mem_regions->region + i;
>
> 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 = range->start;
> + slot_add_mem_req.size = range_len(range);
Similarly here:
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]);
Then remain the kfree paths for "phys_contig_mem_regions.regions"
instead of "phys_contig_mem_regions".
Thanks,
Andra
>
> rc = ne_do_request(pdev, SLOT_ADD_MEM,
> &slot_add_mem_req, sizeof(slot_add_mem_req),
> --
> 1.8.3.1
>
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