Re: [PATCH v11 12/20] x86/virt/tdx: Allocate and set up PAMTs for TDMRs

[kirill . shutemov]

On Mon, Jun 05, 2023 at 02:27:25AM +1200, Kai Huang wrote:
> diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
> index fa9fa8bc581a..5f0499ba5d67 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.c
> +++ b/arch/x86/virt/vmx/tdx/tdx.c
> @@ -265,7 +265,7 @@ static int tdx_get_sysinfo(struct tdsysinfo_struct *sysinfo,
>   * overlap.
>   */
>  static int add_tdx_memblock(struct list_head *tmb_list, unsigned long start_pfn,
> -			    unsigned long end_pfn)
> +			    unsigned long end_pfn, int nid)
>  {
>  	struct tdx_memblock *tmb;
>  
> @@ -276,6 +276,7 @@ static int add_tdx_memblock(struct list_head *tmb_list, unsigned long start_pfn,
>  	INIT_LIST_HEAD(&tmb->list);
>  	tmb->start_pfn = start_pfn;
>  	tmb->end_pfn = end_pfn;
> +	tmb->nid = nid;
>  
>  	/* @tmb_list is protected by mem_hotplug_lock */
>  	list_add_tail(&tmb->list, tmb_list);
> @@ -303,9 +304,9 @@ static void free_tdx_memlist(struct list_head *tmb_list)
>  static int build_tdx_memlist(struct list_head *tmb_list)
>  {
>  	unsigned long start_pfn, end_pfn;
> -	int i, ret;
> +	int i, nid, ret;
>  
> -	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
> +	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
>  		/*
>  		 * The first 1MB is not reported as TDX convertible memory.
>  		 * Although the first 1MB is always reserved and won't end up
> @@ -321,7 +322,7 @@ static int build_tdx_memlist(struct list_head *tmb_list)
>  		 * memblock has already guaranteed they are in address
>  		 * ascending order and don't overlap.
>  		 */
> -		ret = add_tdx_memblock(tmb_list, start_pfn, end_pfn);
> +		ret = add_tdx_memblock(tmb_list, start_pfn, end_pfn, nid);
>  		if (ret)
>  			goto err;
>  	}


These three hunks and change to struct tdx_memblock looks unrelated.
Why not fold this to 09/20?

> @@ -472,6 +473,202 @@ static int fill_out_tdmrs(struct list_head *tmb_list,
>  	return 0;
>  }
>  
> +/*
> + * Calculate PAMT size given a TDMR and a page size.  The returned
> + * PAMT size is always aligned up to 4K page boundary.
> + */
> +static unsigned long tdmr_get_pamt_sz(struct tdmr_info *tdmr, int pgsz,
> +				      u16 pamt_entry_size)
> +{
> +	unsigned long pamt_sz, nr_pamt_entries;
> +
> +	switch (pgsz) {
> +	case TDX_PS_4K:
> +		nr_pamt_entries = tdmr->size >> PAGE_SHIFT;
> +		break;
> +	case TDX_PS_2M:
> +		nr_pamt_entries = tdmr->size >> PMD_SHIFT;
> +		break;
> +	case TDX_PS_1G:
> +		nr_pamt_entries = tdmr->size >> PUD_SHIFT;
> +		break;
> +	default:
> +		WARN_ON_ONCE(1);
> +		return 0;
> +	}
> +
> +	pamt_sz = nr_pamt_entries * pamt_entry_size;
> +	/* TDX requires PAMT size must be 4K aligned */
> +	pamt_sz = ALIGN(pamt_sz, PAGE_SIZE);
> +
> +	return pamt_sz;
> +}
> +
> +/*
> + * Locate a NUMA node which should hold the allocation of the @tdmr
> + * PAMT.  This node will have some memory covered by the TDMR.  The
> + * relative amount of memory covered is not considered.
> + */
> +static int tdmr_get_nid(struct tdmr_info *tdmr, struct list_head *tmb_list)
> +{
> +	struct tdx_memblock *tmb;
> +
> +	/*
> +	 * A TDMR must cover at least part of one TMB.  That TMB will end
> +	 * after the TDMR begins.  But, that TMB may have started before
> +	 * the TDMR.  Find the next 'tmb' that _ends_ after this TDMR
> +	 * begins.  Ignore 'tmb' start addresses.  They are irrelevant.
> +	 */
> +	list_for_each_entry(tmb, tmb_list, list) {
> +		if (tmb->end_pfn > PHYS_PFN(tdmr->base))
> +			return tmb->nid;
> +	}
> +
> +	/*
> +	 * Fall back to allocating the TDMR's metadata from node 0 when
> +	 * no TDX memory block can be found.  This should never happen
> +	 * since TDMRs originate from TDX memory blocks.
> +	 */
> +	pr_warn("TDMR [0x%llx, 0x%llx): unable to find local NUMA node for PAMT allocation, fallback to use node 0.\n",
> +			tdmr->base, tdmr_end(tdmr));
> +	return 0;
> +}
> +
> +#define TDX_PS_NR	(TDX_PS_1G + 1)

This should be next to the rest TDX_PS_*.

> +
> +/*
> + * Allocate PAMTs from the local NUMA node of some memory in @tmb_list
> + * within @tdmr, and set up PAMTs for @tdmr.
> + */
> +static int tdmr_set_up_pamt(struct tdmr_info *tdmr,
> +			    struct list_head *tmb_list,
> +			    u16 pamt_entry_size)
> +{
> +	unsigned long pamt_base[TDX_PS_NR];
> +	unsigned long pamt_size[TDX_PS_NR];
> +	unsigned long tdmr_pamt_base;
> +	unsigned long tdmr_pamt_size;
> +	struct page *pamt;
> +	int pgsz, nid;
> +
> +	nid = tdmr_get_nid(tdmr, tmb_list);
> +
> +	/*
> +	 * Calculate the PAMT size for each TDX supported page size
> +	 * and the total PAMT size.
> +	 */
> +	tdmr_pamt_size = 0;
> +	for (pgsz = TDX_PS_4K; pgsz <= TDX_PS_1G ; pgsz++) {

"< TDX_PS_NR" instead of "<= TDX_PS_1G".

> +		pamt_size[pgsz] = tdmr_get_pamt_sz(tdmr, pgsz,
> +					pamt_entry_size);
> +		tdmr_pamt_size += pamt_size[pgsz];
> +	}
> +
> +	/*
> +	 * Allocate one chunk of physically contiguous memory for all
> +	 * PAMTs.  This helps minimize the PAMT's use of reserved areas
> +	 * in overlapped TDMRs.
> +	 */
> +	pamt = alloc_contig_pages(tdmr_pamt_size >> PAGE_SHIFT, GFP_KERNEL,
> +			nid, &node_online_map);
> +	if (!pamt)
> +		return -ENOMEM;
> +
> +	/*
> +	 * Break the contiguous allocation back up into the
> +	 * individual PAMTs for each page size.
> +	 */
> +	tdmr_pamt_base = page_to_pfn(pamt) << PAGE_SHIFT;
> +	for (pgsz = TDX_PS_4K; pgsz <= TDX_PS_1G; pgsz++) {
> +		pamt_base[pgsz] = tdmr_pamt_base;
> +		tdmr_pamt_base += pamt_size[pgsz];
> +	}
> +
> +	tdmr->pamt_4k_base = pamt_base[TDX_PS_4K];
> +	tdmr->pamt_4k_size = pamt_size[TDX_PS_4K];
> +	tdmr->pamt_2m_base = pamt_base[TDX_PS_2M];
> +	tdmr->pamt_2m_size = pamt_size[TDX_PS_2M];
> +	tdmr->pamt_1g_base = pamt_base[TDX_PS_1G];
> +	tdmr->pamt_1g_size = pamt_size[TDX_PS_1G];
> +
> +	return 0;
> +}
> +
> +static void tdmr_get_pamt(struct tdmr_info *tdmr, unsigned long *pamt_pfn,
> +			  unsigned long *pamt_npages)
> +{
> +	unsigned long pamt_base, pamt_sz;
> +
> +	/*
> +	 * The PAMT was allocated in one contiguous unit.  The 4K PAMT
> +	 * should always point to the beginning of that allocation.
> +	 */
> +	pamt_base = tdmr->pamt_4k_base;
> +	pamt_sz = tdmr->pamt_4k_size + tdmr->pamt_2m_size + tdmr->pamt_1g_size;
> +
> +	*pamt_pfn = PHYS_PFN(pamt_base);
> +	*pamt_npages = pamt_sz >> PAGE_SHIFT;
> +}
> +
> +static void tdmr_free_pamt(struct tdmr_info *tdmr)
> +{
> +	unsigned long pamt_pfn, pamt_npages;
> +
> +	tdmr_get_pamt(tdmr, &pamt_pfn, &pamt_npages);
> +
> +	/* Do nothing if PAMT hasn't been allocated for this TDMR */
> +	if (!pamt_npages)
> +		return;
> +
> +	if (WARN_ON_ONCE(!pamt_pfn))
> +		return;
> +
> +	free_contig_range(pamt_pfn, pamt_npages);
> +}
> +
> +static void tdmrs_free_pamt_all(struct tdmr_info_list *tdmr_list)
> +{
> +	int i;
> +
> +	for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++)
> +		tdmr_free_pamt(tdmr_entry(tdmr_list, i));
> +}
> +
> +/* Allocate and set up PAMTs for all TDMRs */
> +static int tdmrs_set_up_pamt_all(struct tdmr_info_list *tdmr_list,
> +				 struct list_head *tmb_list,
> +				 u16 pamt_entry_size)
> +{
> +	int i, ret = 0;
> +
> +	for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) {
> +		ret = tdmr_set_up_pamt(tdmr_entry(tdmr_list, i), tmb_list,
> +				pamt_entry_size);
> +		if (ret)
> +			goto err;
> +	}
> +
> +	return 0;
> +err:
> +	tdmrs_free_pamt_all(tdmr_list);
> +	return ret;
> +}
> +
> +static unsigned long tdmrs_count_pamt_pages(struct tdmr_info_list *tdmr_list)
> +{
> +	unsigned long pamt_npages = 0;
> +	int i;
> +
> +	for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) {
> +		unsigned long pfn, npages;
> +
> +		tdmr_get_pamt(tdmr_entry(tdmr_list, i), &pfn, &npages);
> +		pamt_npages += npages;
> +	}
> +
> +	return pamt_npages;
> +}
> +
>  /*
>   * 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
> @@ -487,10 +684,13 @@ static int construct_tdmrs(struct list_head *tmb_list,
>  	if (ret)
>  		return ret;
>  
> +	ret = tdmrs_set_up_pamt_all(tdmr_list, tmb_list,
> +			sysinfo->pamt_entry_size);
> +	if (ret)
> +		return ret;
>  	/*
>  	 * TODO:
>  	 *
> -	 *  - Allocate and set up PAMTs for each TDMR.
>  	 *  - Designate reserved areas for each TDMR.
>  	 *
>  	 * Return -EINVAL until constructing TDMRs is done
> @@ -547,6 +747,11 @@ static int init_tdx_module(void)
>  	 *  Return error before all steps are done.
>  	 */
>  	ret = -EINVAL;
> +	if (ret)
> +		tdmrs_free_pamt_all(&tdx_tdmr_list);
> +	else
> +		pr_info("%lu KBs allocated for PAMT.\n",
> +				tdmrs_count_pamt_pages(&tdx_tdmr_list) * 4);

"* 4"? This is very cryptic. procfs uses "<< (PAGE_SHIFT - 10)" which
slightly less magic to me. And just make the helper that returns kilobytes
to begin with, if it is the only caller.

>  out_free_tdmrs:
>  	if (ret)
>  		free_tdmr_list(&tdx_tdmr_list);
> diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h
> index c20848e76469..e8110e1a9980 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.h
> +++ b/arch/x86/virt/vmx/tdx/tdx.h
> @@ -133,6 +133,7 @@ struct tdx_memblock {
>  	struct list_head list;
>  	unsigned long start_pfn;
>  	unsigned long end_pfn;
> +	int nid;
>  };
>  
>  struct tdmr_info_list {
> -- 
> 2.40.1
> 

-- 
  Kiryl Shutsemau / Kirill A. Shutemov