On Tue, Jun 27, 2023 at 02:12:43AM +1200, Kai Huang wrote:
> As the last step of constructing TDMRs, populate reserved areas for all
> TDMRs. For each TDMR, put all memory holes within this TDMR to the
> reserved areas. And for all PAMTs which overlap with this TDMR, put
> all the overlapping parts to reserved areas too.
Reviewed-by: Yuan Yao <yuan.yao@xxxxxxxxx>
>
> Signed-off-by: Kai Huang <kai.huang@xxxxxxxxx>
> Reviewed-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> ---
>
> v11 -> v12:
> - Code change due to tdmr_get_pamt() change from returning pfn/npages to
> base/size
> - Added Kirill's tag
>
> v10 -> v11:
> - No update
>
> v9 -> v10:
> - No change.
>
> v8 -> v9:
> - Added comment around 'tdmr_add_rsvd_area()' to point out it doesn't do
> optimization to save reserved areas. (Dave).
>
> v7 -> v8: (Dave)
> - "set_up" -> "populate" in function name change (Dave).
> - Improved comment suggested by Dave.
> - Other changes due to 'struct tdmr_info_list'.
>
> v6 -> v7:
> - No change.
>
> v5 -> v6:
> - Rebase due to using 'tdx_memblock' instead of memblock.
> - Split tdmr_set_up_rsvd_areas() into two functions to handle memory
> hole and PAMT respectively.
> - Added Isaku's Reviewed-by.
>
>
> ---
> arch/x86/virt/vmx/tdx/tdx.c | 217 ++++++++++++++++++++++++++++++++++--
> 1 file changed, 209 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
> index fd5417577f26..2bcace5cb25c 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.c
> +++ b/arch/x86/virt/vmx/tdx/tdx.c
> @@ -25,6 +25,7 @@
> #include <linux/sizes.h>
> #include <linux/pfn.h>
> #include <linux/align.h>
> +#include <linux/sort.h>
> #include <asm/msr-index.h>
> #include <asm/msr.h>
> #include <asm/archrandom.h>
> @@ -634,6 +635,207 @@ static unsigned long tdmrs_count_pamt_kb(struct tdmr_info_list *tdmr_list)
> return pamt_size / 1024;
> }
>
> +static int tdmr_add_rsvd_area(struct tdmr_info *tdmr, int *p_idx, u64 addr,
> + u64 size, u16 max_reserved_per_tdmr)
> +{
> + struct tdmr_reserved_area *rsvd_areas = tdmr->reserved_areas;
> + int idx = *p_idx;
> +
> + /* Reserved area must be 4K aligned in offset and size */
> + if (WARN_ON(addr & ~PAGE_MASK || size & ~PAGE_MASK))
> + return -EINVAL;
> +
> + if (idx >= max_reserved_per_tdmr) {
> + pr_warn("initialization failed: TDMR [0x%llx, 0x%llx): reserved areas exhausted.\n",
> + tdmr->base, tdmr_end(tdmr));
> + return -ENOSPC;
> + }
> +
> + /*
> + * Consume one reserved area per call. Make no effort to
> + * optimize or reduce the number of reserved areas which are
> + * consumed by contiguous reserved areas, for instance.
> + */
> + rsvd_areas[idx].offset = addr - tdmr->base;
> + rsvd_areas[idx].size = size;
> +
> + *p_idx = idx + 1;
> +
> + return 0;
> +}
> +
> +/*
> + * Go through @tmb_list to find holes between memory areas. If any of
> + * those holes fall within @tdmr, set up a TDMR reserved area to cover
> + * the hole.
> + */
> +static int tdmr_populate_rsvd_holes(struct list_head *tmb_list,
> + struct tdmr_info *tdmr,
> + int *rsvd_idx,
> + u16 max_reserved_per_tdmr)
> +{
> + struct tdx_memblock *tmb;
> + u64 prev_end;
> + int ret;
> +
> + /*
> + * Start looking for reserved blocks at the
> + * beginning of the TDMR.
> + */
> + prev_end = tdmr->base;
> + list_for_each_entry(tmb, tmb_list, list) {
> + u64 start, end;
> +
> + start = PFN_PHYS(tmb->start_pfn);
> + end = PFN_PHYS(tmb->end_pfn);
> +
> + /* Break if this region is after the TDMR */
> + if (start >= tdmr_end(tdmr))
> + break;
> +
> + /* Exclude regions before this TDMR */
> + if (end < tdmr->base)
> + continue;
> +
> + /*
> + * Skip over memory areas that
> + * have already been dealt with.
> + */
> + if (start <= prev_end) {
> + prev_end = end;
> + continue;
> + }
> +
> + /* Add the hole before this region */
> + ret = tdmr_add_rsvd_area(tdmr, rsvd_idx, prev_end,
> + start - prev_end,
> + max_reserved_per_tdmr);
> + if (ret)
> + return ret;
> +
> + prev_end = end;
> + }
> +
> + /* Add the hole after the last region if it exists. */
> + if (prev_end < tdmr_end(tdmr)) {
> + ret = tdmr_add_rsvd_area(tdmr, rsvd_idx, prev_end,
> + tdmr_end(tdmr) - prev_end,
> + max_reserved_per_tdmr);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * Go through @tdmr_list to find all PAMTs. If any of those PAMTs
> + * overlaps with @tdmr, set up a TDMR reserved area to cover the
> + * overlapping part.
> + */
> +static int tdmr_populate_rsvd_pamts(struct tdmr_info_list *tdmr_list,
> + struct tdmr_info *tdmr,
> + int *rsvd_idx,
> + u16 max_reserved_per_tdmr)
> +{
> + int i, ret;
> +
> + for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) {
> + struct tdmr_info *tmp = tdmr_entry(tdmr_list, i);
> + unsigned long pamt_base, pamt_size, pamt_end;
> +
> + tdmr_get_pamt(tmp, &pamt_base, &pamt_size);
> + /* Each TDMR must already have PAMT allocated */
> + WARN_ON_ONCE(!pamt_size|| !pamt_base);
> +
> + pamt_end = pamt_base + pamt_size;
> + /* Skip PAMTs outside of the given TDMR */
> + if ((pamt_end <= tdmr->base) ||
> + (pamt_base >= tdmr_end(tdmr)))
> + continue;
> +
> + /* Only mark the part within the TDMR as reserved */
> + if (pamt_base < tdmr->base)
> + pamt_base = tdmr->base;
> + if (pamt_end > tdmr_end(tdmr))
> + pamt_end = tdmr_end(tdmr);
> +
> + ret = tdmr_add_rsvd_area(tdmr, rsvd_idx, pamt_base,
> + pamt_end - pamt_base,
> + max_reserved_per_tdmr);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +/* Compare function called by sort() for TDMR reserved areas */
> +static int rsvd_area_cmp_func(const void *a, const void *b)
> +{
> + struct tdmr_reserved_area *r1 = (struct tdmr_reserved_area *)a;
> + struct tdmr_reserved_area *r2 = (struct tdmr_reserved_area *)b;
> +
> + if (r1->offset + r1->size <= r2->offset)
> + return -1;
> + if (r1->offset >= r2->offset + r2->size)
> + return 1;
> +
> + /* Reserved areas cannot overlap. The caller must guarantee. */
> + WARN_ON_ONCE(1);
> + return -1;
> +}
> +
> +/*
> + * Populate reserved areas for the given @tdmr, including memory holes
> + * (via @tmb_list) and PAMTs (via @tdmr_list).
> + */
> +static int tdmr_populate_rsvd_areas(struct tdmr_info *tdmr,
> + struct list_head *tmb_list,
> + struct tdmr_info_list *tdmr_list,
> + u16 max_reserved_per_tdmr)
> +{
> + int ret, rsvd_idx = 0;
> +
> + ret = tdmr_populate_rsvd_holes(tmb_list, tdmr, &rsvd_idx,
> + max_reserved_per_tdmr);
> + if (ret)
> + return ret;
> +
> + ret = tdmr_populate_rsvd_pamts(tdmr_list, tdmr, &rsvd_idx,
> + max_reserved_per_tdmr);
> + if (ret)
> + return ret;
> +
> + /* TDX requires reserved areas listed in address ascending order */
> + sort(tdmr->reserved_areas, rsvd_idx, sizeof(struct tdmr_reserved_area),
> + rsvd_area_cmp_func, NULL);
> +
> + return 0;
> +}
> +
> +/*
> + * Populate reserved areas for all TDMRs in @tdmr_list, including memory
> + * holes (via @tmb_list) and PAMTs.
> + */
> +static int tdmrs_populate_rsvd_areas_all(struct tdmr_info_list *tdmr_list,
> + struct list_head *tmb_list,
> + u16 max_reserved_per_tdmr)
> +{
> + int i;
> +
> + for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) {
> + int ret;
> +
> + ret = tdmr_populate_rsvd_areas(tdmr_entry(tdmr_list, i),
> + tmb_list, tdmr_list, max_reserved_per_tdmr);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> /*
> * Construct a list of TDMRs on the preallocated space in @tdmr_list
> * to cover all TDX memory regions in @tmb_list based on the TDX module
> @@ -653,14 +855,13 @@ static int construct_tdmrs(struct list_head *tmb_list,
> sysinfo->pamt_entry_size);
> if (ret)
> return ret;
> - /*
> - * TODO:
> - *
> - * - Designate reserved areas for each TDMR.
> - *
> - * Return -EINVAL until constructing TDMRs is done
> - */
> - return -EINVAL;
> +
> + ret = tdmrs_populate_rsvd_areas_all(tdmr_list, tmb_list,
> + sysinfo->max_reserved_per_tdmr);
> + if (ret)
> + tdmrs_free_pamt_all(tdmr_list);
> +
> + return ret;
> }
>
> static int init_tdx_module(void)
> --
> 2.40.1
>
