On Fri, 3 Nov 2023 07:35:47 +0100
Nico Boehr <nrb@xxxxxxxxxxxxx> wrote:
[...]
> diff --git a/lib/s390x/sie.c b/lib/s390x/sie.c
> index b44febdeaaac..bd907a0ffefa 100644
> --- a/lib/s390x/sie.c
> +++ b/lib/s390x/sie.c
> @@ -15,6 +15,8 @@
> #include <asm/page.h>
> #include <libcflat.h>
> #include <alloc_page.h>
> +#include <vmalloc.h>
> +#include <sclp.h>
>
> void sie_expect_validity(struct vm *vm)
> {
> @@ -111,6 +113,46 @@ void sie_guest_create(struct vm *vm, uint64_t guest_mem, uint64_t guest_mem_len)
> vm->sblk->crycbd = (uint32_t)(uintptr_t)vm->crycb;
> }
>
> +/*
/**
* sie_guest_alloc - Allocate memory [...]
> + * Allocate memory for a guest and map it in virtual address space such that
> + * it is properly aligned.
> + * @guest_size the desired size of the guest in bytes.
* @guest_size: the desired [...]
> + */
let's try to use a consistent style for comments. in many places we use
the kerneldoc style -- let's stick to that
in the future we should pay more attention to the style, there are
several places where we have __almost__ kerneldoc style.
> +uint8_t *sie_guest_alloc(uint64_t guest_size)
> +{
> + pgd_t *root;
> + u8 *guest_phys, *guest_virt;
> + static unsigned long guest_counter = 1;
> + unsigned long i;
reverse Christmas tree, please
> +
> + setup_vm();
> + root = (pgd_t *)(stctg(1) & PAGE_MASK);
> +
> + /*
> + * Start of guest memory in host virtual space needs to be aligned to
> + * 2GB for some environments. It also can't be at 2GB since the memory
> + * allocator stores its page_states metadata there.
> + * Thus we use the next multiple of 4GB after the end of physical
> + * mapping. This also leaves space after end of physical memory so the
> + * page immediately after physical memory is guaranteed not to be
> + * present.
> + */
> + guest_virt = (uint8_t *)ALIGN(get_ram_size() + guest_counter * 4UL * SZ_1G, SZ_2G);
> + guest_counter++;
> +
> + guest_phys = alloc_pages(get_order(guest_size) - 12);
> + /*
> + * Establish a new mapping of the guest memory so it can be 2GB aligned
> + * without actually requiring 2GB physical memory.
> + */
> + for (i = 0; i <= guest_size; i += PAGE_SIZE) {
i < guest_size ?
> + install_page(root, __pa(guest_phys + i), guest_virt + i);
> + }
> + memset(guest_virt, 0, guest_size);
> +
> + return guest_virt;
> +}
> +
> /* Frees the memory that was gathered on initialization */
> void sie_guest_destroy(struct vm *vm)
> {
[...]
