[PATCH v3 hyperv-next 0/4] Drivers: hv: vmbus: Restrict devices and configurations on 'isolated' guests

Changes since v2 [1]:
  - improve/add logging (Michael Kelley)
  - rename 'hypercalls_features' to 'features_b' (Michael Kelley)
  - move VMBus and NVSC version checks after 'for' loop (Michael Kelley)
  - remove/inline helper functions (Michael Kelley)
  - other minor changes (Michael Kelley)

Changes since v1 [2]:
  - improve/add logging (Haiyang Zhang)
  - move NVSC version check after version negotiation (Haiyang Zhang)

[1] https://lkml.kernel.org/r/20210126115641.2527-1-parri.andrea@gmail.com
[1] https://lkml.kernel.org/r/20210119175841.22248-1-parri.andrea@gmail.com

Cc: Thomas Gleixner <redacted>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: x86@kernel.org
Cc: linux-arch@vger.kernel.org
Cc: netdev@vger.kernel.org

Andrea Parri (Microsoft) (4):
  x86/hyperv: Load/save the Isolation Configuration leaf
  Drivers: hv: vmbus: Restrict vmbus_devices on isolated guests
  Drivers: hv: vmbus: Enforce 'VMBus version >= 5.2' on isolated guests
  hv_netvsc: Restrict configurations on isolated guests

 arch/x86/hyperv/hv_init.c          | 15 ++++++++++++
 arch/x86/include/asm/hyperv-tlfs.h | 15 ++++++++++++
 arch/x86/kernel/cpu/mshyperv.c     |  9 +++++++
 drivers/hv/channel_mgmt.c          | 38 ++++++++++++++++++++++++++++++
 drivers/hv/connection.c            |  7 ++++++
 drivers/net/hyperv/netvsc.c        | 18 ++++++++++++--
 include/asm-generic/hyperv-tlfs.h  |  1 +
 include/asm-generic/mshyperv.h     |  5 ++++
 include/linux/hyperv.h             |  1 +
 9 files changed, 107 insertions(+), 2 deletions(-)

-- 
2.25.1

Restrict the NVSP protocol version(s) that will be negotiated with the
host to be NVSP_PROTOCOL_VERSION_61 or greater if the guest is running
isolated.  Moreover, do not advertise the SR-IOV capability and ignore
NVSP_MSG_4_TYPE_SEND_VF_ASSOCIATION messages in isolated guests, which
are not supposed to support SR-IOV.  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) <parri.andrea@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
---
 drivers/net/hyperv/netvsc.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 1510a236aa341..51005f2d4a821 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c

@@ -22,6 +22,7 @@
 #include <linux/prefetch.h>
 
 #include <asm/sync_bitops.h>
+#include <asm/mshyperv.h>
 
 #include "hyperv_net.h"
 #include "netvsc_trace.h"

@@ -544,7 +545,10 @@ static int negotiate_nvsp_ver(struct hv_device *device,
 	init_packet->msg.v2_msg.send_ndis_config.capability.ieee8021q = 1;
 
 	if (nvsp_ver >= NVSP_PROTOCOL_VERSION_5) {
-		init_packet->msg.v2_msg.send_ndis_config.capability.sriov = 1;
+		if (hv_is_isolation_supported())
+			netdev_info(ndev, "SR-IOV not advertised by guests on the host supporting isolation\n");
+		else
+			init_packet->msg.v2_msg.send_ndis_config.capability.sriov = 1;
 
 		/* Teaming bit is needed to receive link speed updates */
 		init_packet->msg.v2_msg.send_ndis_config.capability.teaming = 1;

@@ -591,6 +595,13 @@ static int netvsc_connect_vsp(struct hv_device *device,
 		goto cleanup;
 	}
 
+	if (hv_is_isolation_supported() && net_device->nvsp_version < NVSP_PROTOCOL_VERSION_61) {
+		netdev_err(ndev, "Invalid NVSP version 0x%x (expected >= 0x%x) from the host supporting isolation\n",
+			   net_device->nvsp_version, NVSP_PROTOCOL_VERSION_61);
+		ret = -EPROTO;
+		goto cleanup;
+	}
+
 	pr_debug("Negotiated NVSP version:%x\n", net_device->nvsp_version);
 
 	/* Send the ndis version */

@@ -1357,7 +1368,10 @@ static void netvsc_receive_inband(struct net_device *ndev,
 		break;
 
 	case NVSP_MSG4_TYPE_SEND_VF_ASSOCIATION:
-		netvsc_send_vf(ndev, nvmsg, msglen);
+		if (hv_is_isolation_supported())
+			netdev_err(ndev, "Ignore VF_ASSOCIATION msg from the host supporting isolation\n");
+		else
+			netvsc_send_vf(ndev, nvmsg, msglen);
 		break;
 	}
 }

-- 
2.25.1

From: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Sent: Monday, February 1, 2021 6:48 AM

Reviewed-by: Michael Kelley <redacted>

On Mon, Feb 01, 2021 at 03:48:10PM +0100, Andrea Parri (Microsoft) wrote:

Andrea Parri (Microsoft) (4):
  x86/hyperv: Load/save the Isolation Configuration leaf
  Drivers: hv: vmbus: Restrict vmbus_devices on isolated guests
  Drivers: hv: vmbus: Enforce 'VMBus version >= 5.2' on isolated guests
  hv_netvsc: Restrict configurations on isolated guests

Applied to hyperv-next. Thanks.

Wei.