Allocate PAMT memory for TDH.MNG.CREATE and TDH.MNG.ADDCX.

PAMT memory that is associated with pages successfully added to the TD
with TDH.MNG.ADDCX will be removed in tdx_reclaim_page() on
tdx_reclaim_control_page().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/x86/kvm/vmx/tdx.c | 41 +++++++++++++++++++++++++++++++----------
 1 file changed, 31 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index ea7e2d93fb44..59bbae2df485 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -399,6 +399,31 @@ static void tdx_pamt_put(struct page *page)
 	tdx_free_pamt_pages(&pamt_pages);
 }
 
+static struct page *tdx_alloc_page(void)
+{
+	struct page *page;
+
+	page = alloc_page(GFP_KERNEL);
+	if (!page)
+		return NULL;
+
+	if (tdx_pamt_get(page)) {
+		__free_page(page);
+		return NULL;
+	}
+
+	return page;
+}
+
+static void tdx_free_page(struct page *page)
+{
+	if (!page)
+		return;
+
+	tdx_pamt_put(page);
+	__free_page(page);
+}
+
 static void tdx_clear_page(struct page *page)
 {
 	const void *zero_page = (const void *) page_to_virt(ZERO_PAGE(0));
@@ -2499,7 +2524,7 @@ static int __tdx_td_init(struct kvm *kvm, struct td_params *td_params,
 
 	atomic_inc(&nr_configured_hkid);
 
-	tdr_page = alloc_page(GFP_KERNEL);
+	tdr_page = tdx_alloc_page();
 	if (!tdr_page)
 		goto free_hkid;
 
@@ -2512,7 +2537,7 @@ static int __tdx_td_init(struct kvm *kvm, struct td_params *td_params,
 		goto free_tdr;
 
 	for (i = 0; i < kvm_tdx->td.tdcs_nr_pages; i++) {
-		tdcs_pages[i] = alloc_page(GFP_KERNEL);
+		tdcs_pages[i] = tdx_alloc_page();
 		if (!tdcs_pages[i])
 			goto free_tdcs;
 	}
@@ -2633,10 +2658,8 @@ static int __tdx_td_init(struct kvm *kvm, struct td_params *td_params,
 teardown:
 	/* Only free pages not yet added, so start at 'i' */
 	for (; i < kvm_tdx->td.tdcs_nr_pages; i++) {
-		if (tdcs_pages[i]) {
-			__free_page(tdcs_pages[i]);
-			tdcs_pages[i] = NULL;
-		}
+		tdx_free_page(tdcs_pages[i]);
+		tdcs_pages[i] = NULL;
 	}
 	if (!kvm_tdx->td.tdcs_pages)
 		kfree(tdcs_pages);
@@ -2652,15 +2675,13 @@ static int __tdx_td_init(struct kvm *kvm, struct td_params *td_params,
 
 free_tdcs:
 	for (i = 0; i < kvm_tdx->td.tdcs_nr_pages; i++) {
-		if (tdcs_pages[i])
-			__free_page(tdcs_pages[i]);
+		tdx_free_page(tdcs_pages[i]);
 	}
 	kfree(tdcs_pages);
 	kvm_tdx->td.tdcs_pages = NULL;
 
 free_tdr:
-	if (tdr_page)
-		__free_page(tdr_page);
+	tdx_free_page(tdr_page);
 	kvm_tdx->td.tdr_page = 0;
 
 free_hkid:
-- 
2.47.2

On Fri, 2025-05-02 at 16:08 +0300, Kirill A. Shutemov wrote:
>  
> +static struct page *tdx_alloc_page(void)
> +{
> +	struct page *page;
> +
> +	page = alloc_page(GFP_KERNEL);
> +	if (!page)
> +		return NULL;
> +
> +	if (tdx_pamt_get(page)) {
> +		__free_page(page);
> +		return NULL;
> +	}
> +
> +	return page;
> +}
> +
> +static void tdx_free_page(struct page *page)
> +{
> +	if (!page)
> +		return;
> +
> +	tdx_pamt_put(page);
> +	__free_page(page);
> +}
> +

IMO the two should be moved to the TDX core code, and exported for KVM to use.

They can be used for other kernel components for TDX Connect.