From 153fcabb00c725ffd604828111752b4e65725787 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Sun, 24 May 2020 17:50:37 +0200
Subject: [PATCH] pc, pc64: fix wrong mtrr physmask() for machines without
 extended address size msr

---
 sys/src/9/pc/mtrr.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sys/src/9/pc/mtrr.c b/sys/src/9/pc/mtrr.c
index 3c41cd275..4b1558bfe 100644
--- a/sys/src/9/pc/mtrr.c
+++ b/sys/src/9/pc/mtrr.c
@@ -113,6 +113,8 @@ physmask(void)
 	if(regs[0] >= Extaddrsz) {			/* ax */
 		cpuid(Extaddrsz, regs);
 		mask = (1LL << (regs[0] & 0xFF)) - 1;	/* ax */
+	} else {
+		mask &= (1LL << 36) - 1;
 	}
 	return mask;
 }