commit b8209544296edbd1af186e2ea9c648642c37b18c upstream.
The VMBUS_RING_SIZE macro adds space for a ring buffer header to the
requested ring buffer size. The header size is always 1 page, and so
its size varies based on the PAGE_SIZE for which the kernel is built.
If the requested ring buffer size is a large power-of-2 size and the header
size is small, the resulting size is inefficient in its use of memory.
For example, a 512 Kbyte ring buffer with a 4 Kbyte page size results in
a 516 Kbyte allocation, which is rounded to up 1 Mbyte by the memory
allocator, and wastes 508 Kbytes of memory.
In such situations, the exact size of the ring buffer isn't that important,
and it's OK to allocate the 4 Kbyte header at the beginning of the 512
Kbytes, leaving the ring buffer itself with just 508 Kbytes. The memory
allocation can be 512 Kbytes instead of 1 Mbyte and nothing is wasted.
Update VMBUS_RING_SIZE to implement this approach for "large" ring buffer
sizes. "Large" is somewhat arbitrarily defined as 8 times the size of
the ring buffer header (which is of size PAGE_SIZE). For example, for
4 Kbyte PAGE_SIZE, ring buffers of 32 Kbytes and larger use the first
4 Kbytes as the ring buffer header. For 64 Kbyte PAGE_SIZE, ring buffers
of 512 Kbytes and larger use the first 64 Kbytes as the ring buffer
header. In both cases, smaller sizes add space for the header so
the ring size isn't reduced too much by using part of the space for
the header. For example, with a 64 Kbyte page size, we don't want
a 128 Kbyte ring buffer to be reduced to 64 Kbytes by allocating half
of the space for the header. In such a case, the memory allocation
is less efficient, but it's the best that can be done.
While the new algorithm slightly changes the amount of space allocated
for ring buffers by drivers that use VMBUS_RING_SIZE, the devices aren't
known to be sensitive to small changes in ring buffer size, so there
shouldn't be any effect.
Fixes: c1135c7fd0e9 ("Drivers: hv: vmbus: Introduce types of GPADL")
Fixes: 6941f67ad37d ("hv_netvsc: Calculate correct ring size when PAGE_SIZE is not 4 Kbytes")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218502
Cc: stable@vger.kernel.org
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Tested-by: Souradeep Chakrabarti <schakrabarti@linux.microsoft.com>
Link: https://lore.kernel.org/r/20240229004533.313662-1-mhklinux@outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20240229004533.313662-1-mhklinux@outlook.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 4d18fcc95f50950a99bd940d4e61a983f91d267a ]
Currently, pointers to guest memory are passed to Hyper-V as
transaction IDs in netvsc. In the face of errors or malicious
behavior in Hyper-V, netvsc should not expose or trust the transaction
IDs returned by Hyper-V to be valid guest memory addresses. Instead,
use small integers generated by vmbus_requestor as requests
(transaction) IDs.
Signed-off-by: Andres Beltran <lkmlabelt@gmail.com>
Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/20201109100402.8946-4-parri.andrea@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Stable-dep-of: 9cae43da9867 ("hv_netvsc: Register VF in netvsc_probe if NET_DEVICE_REGISTER missed")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e8b7db38449ac5b950a3f00519171c4be3e226ff ]
Currently, VMbus drivers use pointers into guest memory as request IDs
for interactions with Hyper-V. To be more robust in the face of errors
or malicious behavior from a compromised Hyper-V, avoid exposing
guest memory addresses to Hyper-V. Also avoid Hyper-V giving back a
bad request ID that is then treated as the address of a guest data
structure with no validation. Instead, encapsulate these memory
addresses and provide small integers as request IDs.
Signed-off-by: Andres Beltran <lkmlabelt@gmail.com>
Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20201109100402.8946-2-parri.andrea@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Stable-dep-of: 9cae43da9867 ("hv_netvsc: Register VF in netvsc_probe if NET_DEVICE_REGISTER missed")
Signed-off-by: Sasha Levin <sashal@kernel.org>
