Commit dde3b60d authored by Kai Huang's avatar Kai Huang Committed by Dave Hansen
Browse files

x86/virt/tdx: Designate reserved areas for all TDMRs 



As the last step of constructing TDMRs, populate reserved areas for all
TDMRs.  Cover all memory holes and PAMTs with a TMDR reserved area.

[ dhansen: trim down chagnelog ]

Signed-off-by: default avatarKai Huang <kai.huang@intel.com>
Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: default avatarIsaku Yamahata <isaku.yamahata@intel.com>
Reviewed-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: default avatarYuan Yao <yuan.yao@intel.com>
Reviewed-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20231208170740.53979-12-dave.hansen%40intel.com
parent ac3a2208

arch/x86/virt/vmx/tdx/tdx.c

+209 −8
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#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/cpufeature.h>
@@ -662,6 +663,207 @@ 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
@@ -681,14 +883,13 @@ static int construct_tdmrs(struct list_head *tmb_list, 
			tdmr_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,

			tdmr_sysinfo->max_reserved_per_tdmr);

	if (ret)

		tdmrs_free_pamt_all(tdmr_list);



	return ret;

}



static int init_tdx_module(void)