MFC r315968:

Provide less laborius way to enable busdma DMAR to only short list of devices.

1 files changed, 23 insertions, 3 deletions

diff --git a/sys/x86/iommu/busdma_dmar.c b/sys/x86/iommu/busdma_dmar.c
index 434ae82..73bf8b2 100644
--- a/sys/x86/iommu/busdma_dmar.c
+++ b/sys/x86/iommu/busdma_dmar.c
@@ -74,14 +74,34 @@ static bool
 dmar_bus_dma_is_dev_disabled(int domain, int bus, int slot, int func)
 {
 	char str[128], *env;
+	int default_bounce;
+	bool ret;
+	static const char bounce_str[] = "bounce";
+	static const char dmar_str[] = "dmar";
+
+	default_bounce = 0;
+	env = kern_getenv("hw.busdma.default");
+	if (env != NULL) {
+		if (strcmp(env, bounce_str) == 0)
+			default_bounce = 1;
+		else if (strcmp(env, dmar_str) == 0)
+			default_bounce = 0;
+		freeenv(env);
+	}
 
-	snprintf(str, sizeof(str), "hw.busdma.pci%d.%d.%d.%d.bounce",
+	snprintf(str, sizeof(str), "hw.busdma.pci%d.%d.%d.%d",
 	    domain, bus, slot, func);
 	env = kern_getenv(str);
 	if (env == NULL)
-		return (false);
+		return (default_bounce != 0);
+	if (strcmp(env, bounce_str) == 0)
+		ret = true;
+	else if (strcmp(env, dmar_str) == 0)
+		ret = false;
+	else
+		ret = default_bounce != 0;
 	freeenv(env);
-	return (true);
+	return (ret);
 }
 
 /*