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From: Dexuan Cui <decui@microsoft.com>
To: "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Sasha Levin <Alexander.Levin@microsoft.com>,
	"sashal@kernel.org" <sashal@kernel.org>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	KY Srinivasan <kys@microsoft.com>,
	Michael Kelley <mikelley@microsoft.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Dexuan Cui <decui@microsoft.com>
Subject: [PATCH 5/7] Drivers: hv: vmbus: Ignore the offers when resuming from hibernation
Date: Tue, 9 Jul 2019 05:29:29 +0000	[thread overview]
Message-ID: <1562650084-99874-6-git-send-email-decui@microsoft.com> (raw)
In-Reply-To: <1562650084-99874-1-git-send-email-decui@microsoft.com>

When the VM resumes, the host re-sends the offers. We should not add the
offers to the global vmbus_connection.chn_list again.

Added some debug code, in case the host screws up the exact info related to
the offers.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
 drivers/hv/channel_mgmt.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index addcef5..a9aeeab 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -854,12 +854,38 @@ void vmbus_initiate_unload(bool crash)
 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 {
 	struct vmbus_channel_offer_channel *offer;
-	struct vmbus_channel *newchannel;
+	struct vmbus_channel *oldchannel, *newchannel;
+	size_t offer_sz;
 
 	offer = (struct vmbus_channel_offer_channel *)hdr;
 
 	trace_vmbus_onoffer(offer);
 
+	mutex_lock(&vmbus_connection.channel_mutex);
+	oldchannel = relid2channel(offer->child_relid);
+	mutex_unlock(&vmbus_connection.channel_mutex);
+
+	if (oldchannel != NULL) {
+		atomic_dec(&vmbus_connection.offer_in_progress);
+
+		/*
+		 * We're resuming from hibernation: we expect the host to send
+		 * exactly the same offers that we had before the hibernation.
+		 */
+		offer_sz = sizeof(*offer);
+		if (memcmp(offer, &oldchannel->offermsg, offer_sz) == 0)
+			return;
+
+		pr_err("Mismatched offer from the host (relid=%d)!\n",
+		       offer->child_relid);
+
+		print_hex_dump_debug("Old vmbus offer: ", DUMP_PREFIX_OFFSET, 4,
+				     4, &oldchannel->offermsg, offer_sz, false);
+		print_hex_dump_debug("New vmbus offer: ", DUMP_PREFIX_OFFSET, 4,
+				     4, offer, offer_sz, false);
+		return;
+	}
+
 	/* Allocate the channel object and save this offer. */
 	newchannel = alloc_channel();
 	if (!newchannel) {
-- 
1.8.3.1


  parent reply	other threads:[~2019-07-09  5:29 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-09  5:29 [PATCH 0/7] Enhance the hv_vmbus driver to support hibernation Dexuan Cui
2019-07-09  5:29 ` [PATCH 1/7] x86/hyper-v: Suspend/resume the hypercall page for hibernation Dexuan Cui
2019-07-30 22:18   ` Michael Kelley
2019-07-09  5:29 ` [PATCH 2/7] clocksource/drivers: Suspend/resume Hyper-V clocksource " Dexuan Cui
2019-07-30 22:23   ` Michael Kelley
2019-07-09  5:29 ` [PATCH 3/7] Drivers: hv: vmbus: Split hv_synic_init/cleanup into regs and timer settings Dexuan Cui
2019-07-30 22:35   ` Michael Kelley
2019-07-30 23:18     ` Dexuan Cui
2019-07-09  5:29 ` [PATCH 4/7] Drivers: hv: vmbus: Suspend/resume the synic for hibernation Dexuan Cui
2019-07-09  5:29 ` Dexuan Cui [this message]
2019-07-30 23:07   ` [PATCH 5/7] Drivers: hv: vmbus: Ignore the offers when resuming from hibernation Michael Kelley
2019-07-31  0:01     ` Dexuan Cui
2019-07-09  5:29 ` [PATCH 6/7] Drivers: hv: vmbus: Suspend/resume the vmbus itself for hibernation Dexuan Cui
2019-07-30 23:25   ` Michael Kelley
2019-07-31  0:16     ` Dexuan Cui
2019-07-09  5:29 ` [PATCH 7/7] Drivers: hv: vmbus: Implement suspend/resume for VSC drivers " Dexuan Cui
2019-07-30 23:38   ` Michael Kelley

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