RE: [PATCH Part2 v6 07/49] x86/sev: Invalid pages from direct map when adding it to RMP table

[AMD Official Use Only - General]

Hello Boris,

quoted

Subject: x86/sev: Invalid pages from direct map when adding it to RMP 
table

"...: Invalidate pages from the direct map when adding them to the RMP table"

Ok

quoted

+static int restore_direct_map(u64 pfn, int npages) {
+	int i, ret = 0;
+
+	for (i = 0; i < npages; i++) {
+		ret = set_direct_map_default_noflush(pfn_to_page(pfn + i));

set_memory_p() ?

You mean set_memory_present() ? 

Is there an issue with not using set_direct_map_default_noflush(), it is easier to correlate with
this function and it's functionality of restoring the page in the kernel direct map ?

+		if (ret)
+			goto cleanup;
+	}
+
+cleanup:
+	WARN(ret > 0, "Failed to restore direct map for pfn 0x%llx\n", pfn + 
+i);

Warn for each pfn?!

That'll flood dmesg mightily.

+	return ret;
+}
+
+static int invalid_direct_map(unsigned long pfn, int npages) {
+	int i, ret = 0;
+
+	for (i = 0; i < npages; i++) {
+		ret = set_direct_map_invalid_noflush(pfn_to_page(pfn + i));

As above, set_memory_np() doesn't work here instead of looping over each page?

Yes, set_memory_np() looks more efficient to use instead of looping over each page.

But again, calling set_direct_map_invalid_noflush() is easier to understand from the
calling function's point of view as it correlates to the functionality of invalidating the 
page from kernel direct map ? 

quoted

+	if (val->assigned) {
+		if (invalid_direct_map(pfn, npages)) {

. +			pr_err("Failed to unmap pfn 0x%llx pages %d from direct_map\n",

"Failed to unmap %d pages at pfn 0x... from the direct map\n"

Ok.

quoted

+	if (!ret && !val->assigned) {
+		if (restore_direct_map(pfn, npages)) {
+			pr_err("Failed to map pfn 0x%llx pages %d in direct_map\n",

"Failed to map %d pages at pfn 0x... into the direct map\n"

Ok.

Thanks,
Ashish