On 2025-06-25 06:27, Jan Beulich wrote:
On 16.06.2025 15:02, Jan Beulich wrote:
--- /dev/null
+++ b/xen/arch/x86/scrub_page.S
@@ -0,0 +1,39 @@
+ .file __FILE__
+
+#include <asm/asm_defns.h>
+#include <xen/page-size.h>
+#include <xen/scrub.h>
+
+FUNC(scrub_page_cold)
+ mov $PAGE_SIZE/32, %ecx
+ mov $SCRUB_PATTERN, %rax
+
+0: movnti %rax, (%rdi)
+ movnti %rax, 8(%rdi)
+ movnti %rax, 16(%rdi)
+ movnti %rax, 24(%rdi)
+ add $32, %rdi
+ sub $1, %ecx
+ jnz 0b
+
+ sfence
+ ret
+END(scrub_page_cold)
+
+ .macro scrub_page_stosb
+ mov $PAGE_SIZE, %ecx
+ mov $SCRUB_BYTE_PATTERN, %eax
+ rep stosb
+ ret
+ .endm
+
+ .macro scrub_page_stosq
+ mov $PAGE_SIZE/8, %ecx
+ mov $SCRUB_PATTERN, %rax
+ rep stosq
+ ret
+ .endm
+
+FUNC(scrub_page_hot)
+ ALTERNATIVE scrub_page_stosq, scrub_page_stosb, X86_FEATURE_ERMS
+END(scrub_page_hot)
Bah, I've noticed only now that I failed to do the ret -> RET conversion here
during the most recent re-basing.
Good job catching that. My R-b still applies with the RET fixup.
Regards,
Jason
