git: 50d7d967bbfd - main - xen/privcmd: fix MMAP_RESOURCE ioctl to copy out results

From: Roger Pau Monné <royger_at_FreeBSD.org>
Date: Thu, 18 Nov 2021 08:47:00 UTC
The branch main has been updated by royger:

URL: https://cgit.FreeBSD.org/src/commit/?id=50d7d967bbfdcaf38bfac1c3bcc985a31fed26ab

commit 50d7d967bbfdcaf38bfac1c3bcc985a31fed26ab
Author:     Roger Pau Monné <royger@FreeBSD.org>
AuthorDate: 2021-11-17 10:48:35 +0000
Commit:     Roger Pau Monné <royger@FreeBSD.org>
CommitDate: 2021-11-18 08:46:44 +0000

    xen/privcmd: fix MMAP_RESOURCE ioctl to copy out results
    
    The current definition for the MMAP_RESOURCE ioctl was wrong as it
    didn't copy back the result to the caller. Fix the definition and also
    remove the bogus attempt to copy the result in the implementation.
    
    Note such copy back is only needed when querying the size of a
    resource.
    
    Sponsored by: Citrix Systems R&D
---
 sys/dev/xen/privcmd/privcmd.c | 8 +++-----
 sys/xen/privcmd.h             | 2 +-
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/sys/dev/xen/privcmd/privcmd.c b/sys/dev/xen/privcmd/privcmd.c
index 0ef6737df64f..763c2f471c4f 100644
--- a/sys/dev/xen/privcmd/privcmd.c
+++ b/sys/dev/xen/privcmd/privcmd.c
@@ -426,12 +426,10 @@ mmap_out:
 		if (mmap->addr == 0 && mmap->num == 0) {
 			error = HYPERVISOR_memory_op(XENMEM_acquire_resource,
 			    &adq);
-			if (error != 0) {
+			if (error != 0)
 				error = xen_translate_error(error);
-				break;
-			}
-			error = copyout(&adq.nr_frames, &mmap->num,
-			    sizeof(mmap->num));
+			else
+				mmap->num = adq.nr_frames;
 			break;
 		}
 
diff --git a/sys/xen/privcmd.h b/sys/xen/privcmd.h
index 55a1cdc86471..605ba018ac34 100644
--- a/sys/xen/privcmd.h
+++ b/sys/xen/privcmd.h
@@ -79,7 +79,7 @@ struct ioctl_privcmd_dmop {
 #define IOCTL_PRIVCMD_MMAPBATCH					\
 	_IOWR('E', 1, struct ioctl_privcmd_mmapbatch)
 #define IOCTL_PRIVCMD_MMAP_RESOURCE				\
-	_IOW('E', 2, struct ioctl_privcmd_mmapresource)
+	_IOWR('E', 2, struct ioctl_privcmd_mmapresource)
 #define IOCTL_PRIVCMD_DM_OP					\
 	_IOW('E', 3, struct ioctl_privcmd_dmop)
 #define IOCTL_PRIVCMD_RESTRICT					\