From 7ef4b2f0d9adb73eb66e1f87f22953169c3dc7f8 Mon Sep 17 00:00:00 2001 From: Andrea Parri (Microsoft) Date: Mon, 1 Feb 2021 15:48:13 +0100 Subject: Drivers: hv: vmbus: Enforce 'VMBus version >= 5.2' on isolated guests Restrict the protocol version(s) that will be negotiated with the host to be 5.2 or greater if the guest is running isolated. This reduces the footprint of the code that will be exercised by Confidential VMs and hence the exposure to bugs and vulnerabilities. Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20210201144814.2701-4-parri.andrea@gmail.com Signed-off-by: Wei Liu --- drivers/hv/connection.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c index 11170d9a2e1a..c83612cddb99 100644 --- a/drivers/hv/connection.c +++ b/drivers/hv/connection.c @@ -244,6 +244,13 @@ int vmbus_connect(void) break; } + if (hv_is_isolation_supported() && version < VERSION_WIN10_V5_2) { + pr_err("Invalid VMBus version %d.%d (expected >= %d.%d) from the host supporting isolation\n", + version >> 16, version & 0xFFFF, VERSION_WIN10_V5_2 >> 16, VERSION_WIN10_V5_2 & 0xFFFF); + ret = -EINVAL; + goto cleanup; + } + vmbus_proto_version = version; pr_info("Vmbus version:%d.%d\n", version >> 16, version & 0xFFFF); -- cgit v1.2.3