[PATCH v4 7/7] crypto/ccp: Update HV_FIXED page states to allow freeing of memory

[Tycho Andersen <tycho@kernel.org>]

From: Tom Lendacky <thomas.lendacky@amd.com>

After SNP is disabled, any pages allocated as HV_FIXED can now be freed.
Update the page state of these pages and the snp_leak_hv_fixed_pages()
function to free pages on SNP_SHUTDOWN.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Tycho Andersen (AMD) <tycho@kernel.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
---
 drivers/crypto/ccp/sev-dev.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 366303ff6466..939fa8aa155c 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -1219,7 +1219,7 @@ static void snp_add_hv_fixed_pages(struct sev_device *sev, struct sev_data_range
 
 static void snp_leak_hv_fixed_pages(void)
 {
-	struct snp_hv_fixed_pages_entry *entry;
+	struct snp_hv_fixed_pages_entry *entry, *nentry;
 
 	/* List is protected by sev_cmd_mutex */
 	lockdep_assert_held(&sev_cmd_mutex);
@@ -1227,10 +1227,16 @@ static void snp_leak_hv_fixed_pages(void)
 	if (list_empty(&snp_hv_fixed_pages))
 		return;
 
-	list_for_each_entry(entry, &snp_hv_fixed_pages, list)
-		if (entry->page_state == HV_FIXED)
+	list_for_each_entry_safe(entry, nentry, &snp_hv_fixed_pages, list) {
+		if (entry->free && entry->page_state != HV_FIXED)
+			__free_pages(entry->page, entry->order);
+		else
 			__snp_leak_pages(page_to_pfn(entry->page),
 					 1 << entry->order, false);
+
+		list_del(&entry->list);
+		kfree(entry);
+	}
 }
 
 bool sev_is_snp_ciphertext_hiding_supported(void)
@@ -2077,6 +2083,7 @@ static int __sev_snp_shutdown_locked(int *error, bool panic)
 	if (data.x86_snp_shutdown) {
 		if (!panic)
 			snp_shutdown();
+		snp_hv_fixed_pages_state_update(sev, ALLOCATED);
 	} else {
 		/*
 		 * SNP_SHUTDOWN_EX with IOMMU_SNP_SHUTDOWN set to 1 disables SNP
-- 
2.53.0