From d8e1fd6eda930f5b4c8ba531a5c84ca0cd54d318 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Duval?= <jerome.duval@gmail.com>
Date: Wed, 18 Mar 2020 10:05:50 +0100
Subject: [PATCH] virtio: add clear_feature hook.

Change-Id: I282ffc65a7bd692145626ab4272c5df4a792e9d4
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2383
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
---
 headers/private/virtio/virtio.h                       |  2 ++
 .../kernel/bus_managers/virtio/VirtioDevice.cpp       |  8 ++++++++
 .../kernel/bus_managers/virtio/VirtioModule.cpp       | 11 +++++++++++
 .../kernel/bus_managers/virtio/VirtioPrivate.h        |  1 +
 4 files changed, 22 insertions(+)

diff --git a/headers/private/virtio/virtio.h b/headers/private/virtio/virtio.h
index cb0c1760e6..2e17f725c1 100644
--- a/headers/private/virtio/virtio.h
+++ b/headers/private/virtio/virtio.h
@@ -101,6 +101,8 @@ typedef struct {
 	status_t (*negotiate_features)(virtio_device cookie, uint32 supported,
 		uint32* negotiated, const char* (*get_feature_name)(uint32));
 
+	status_t (*clear_feature)(virtio_device cookie, uint32 feature);
+
 	status_t (*read_device_config)(virtio_device cookie, uint8 offset,
 		void* buffer, size_t bufferSize);
 	status_t (*write_device_config)(virtio_device cookie, uint8 offset,
diff --git a/src/add-ons/kernel/bus_managers/virtio/VirtioDevice.cpp b/src/add-ons/kernel/bus_managers/virtio/VirtioDevice.cpp
index 012f192598..2ef33a7fad 100644
--- a/src/add-ons/kernel/bus_managers/virtio/VirtioDevice.cpp
+++ b/src/add-ons/kernel/bus_managers/virtio/VirtioDevice.cpp
@@ -126,6 +126,14 @@ VirtioDevice::NegotiateFeatures(uint32 supported, uint32* negotiated,
 }
 
 
+status_t
+VirtioDevice::ClearFeature(uint32 feature)
+{
+	fFeatures &= ~feature;
+	return fController->write_guest_features(fCookie, fFeatures);
+}
+
+
 status_t
 VirtioDevice::ReadDeviceConfig(uint8 offset, void* buffer, size_t bufferSize)
 {
diff --git a/src/add-ons/kernel/bus_managers/virtio/VirtioModule.cpp b/src/add-ons/kernel/bus_managers/virtio/VirtioModule.cpp
index 4ad32a019d..3bfecb7fb3 100644
--- a/src/add-ons/kernel/bus_managers/virtio/VirtioModule.cpp
+++ b/src/add-ons/kernel/bus_managers/virtio/VirtioModule.cpp
@@ -63,6 +63,16 @@ virtio_negotiate_features(void* _device, uint32 supported,
 }
 
 
+status_t
+virtio_clear_feature(void* _device, uint32 feature)
+{
+	CALLED();
+	VirtioDevice *device = (VirtioDevice *)_device;
+
+	return device->ClearFeature(feature);
+}
+
+
 status_t
 virtio_read_device_config(void* _device, uint8 offset, void* buffer,
 		size_t bufferSize)
@@ -275,6 +285,7 @@ virtio_device_interface virtio_device_module = {
 	},
 
 	virtio_negotiate_features,
+	virtio_clear_feature,
 	virtio_read_device_config,
 	virtio_write_device_config,
 	virtio_alloc_queues,
diff --git a/src/add-ons/kernel/bus_managers/virtio/VirtioPrivate.h b/src/add-ons/kernel/bus_managers/virtio/VirtioPrivate.h
index 5a1b7dbc3a..e91244d012 100644
--- a/src/add-ons/kernel/bus_managers/virtio/VirtioPrivate.h
+++ b/src/add-ons/kernel/bus_managers/virtio/VirtioPrivate.h
@@ -48,6 +48,7 @@ public:
 			status_t 			NegotiateFeatures(uint32 supported,
 									uint32* negotiated,
 									const char* (*get_feature_name)(uint32));
+			status_t 			ClearFeature(uint32 feature);
 
 			status_t			ReadDeviceConfig(uint8 offset, void* buffer,
 									size_t bufferSize);