linux-kernel - [PATCH 1/1] Drivers: hv: vmbus: Rework use of DMA_BIT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1644176216-12531-1-git-send-email-mikelley@microsoft.com>
Date:   Sun,  6 Feb 2022 11:36:56 -0800
From:   Michael Kelley <mikelley@...rosoft.com>
To:     kys@...rosoft.com, haiyangz@...rosoft.com, sthemmin@...rosoft.com,
        wei.liu@...nel.org, tianyu.lan@...rosoft.com, longli@...rosoft.com,
        nathan@...nel.org, ndesaulniers@...gle.com, vt@...linux.org,
        kuba@...nel.org, linux-kernel@...r.kernel.org,
        linux-hyperv@...r.kernel.org, llvm@...ts.linux.dev
Cc:     mikelley@...rosoft.com
Subject: [PATCH 1/1] Drivers: hv: vmbus: Rework use of DMA_BIT_MASK(64)

Using DMA_BIT_MASK(64) as an initializer for a global variable
causes problems with Clang 12.0.1. The compiler doesn't understand
that value 64 is excluded from the shift at compile time, resulting
in a build error.

While this is a compiler problem, avoid the issue by setting up
the dma_mask memory as part of struct hv_device, and initialize
it using dma_set_mask().

Reported-by: Nathan Chancellor <nathan@...nel.org>
Reported-by: Vitaly Chikunov <vt@...linux.org>
Reported-by: Jakub Kicinski <kuba@...nel.org>
Fixes: 743b237c3a7b ("scsi: storvsc: Add Isolation VM support for storvsc driver")
Signed-off-by: Michael Kelley <mikelley@...rosoft.com>
---
 drivers/hv/vmbus_drv.c | 4 ++--
 include/linux/hyperv.h | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 17bf55f..0d96634 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2079,7 +2079,6 @@ struct hv_device *vmbus_device_create(const guid_t *type,
 	return child_device_obj;
 }
 
-static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
 /*
  * vmbus_device_register - Register the child device
  */
@@ -2120,8 +2119,9 @@ int vmbus_device_register(struct hv_device *child_device_obj)
 	}
 	hv_debug_add_dev_dir(child_device_obj);
 
-	child_device_obj->device.dma_mask = &vmbus_dma_mask;
 	child_device_obj->device.dma_parms = &child_device_obj->dma_parms;
+	child_device_obj->device.dma_mask = &child_device_obj->dma_mask;
+	dma_set_mask(&child_device_obj->device, DMA_BIT_MASK(64));
 	return 0;
 
 err_kset_unregister:
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index f565a89..fe2e017 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1262,6 +1262,7 @@ struct hv_device {
 	struct vmbus_channel *channel;
 	struct kset	     *channels_kset;
 	struct device_dma_parameters dma_parms;
+	u64 dma_mask;
 
 	/* place holder to keep track of the dir for hv device in debugfs */
 	struct dentry *debug_dir;
-- 
1.8.3.1