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From:   Nuno Das Neves <nunodasneves@linux.microsoft.com>
To:     linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     mikelley@microsoft.com, kys@microsoft.com, wei.liu@kernel.org,
        haiyangz@microsoft.com, decui@microsoft.com
Subject: [PATCH] Drivers: hv: Do not free synic pages when they were not allocated
Date:   Mon,  3 Apr 2023 16:22:02 -0700
Message-Id: <1680564122-30819-1-git-send-email-nunodasneves@linux.microsoft.com>
Precedence: bulk

In case of root partition or snp, the synic pages are allocated by the
hypervisor instead of the kernel, so they should not be freed.

Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
---
 drivers/hv/hv.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index c7f7652932ca..a10cf642c9ad 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -193,8 +193,10 @@ void hv_synic_free(void)
 		struct hv_per_cpu_context *hv_cpu
 			= per_cpu_ptr(hv_context.cpu_context, cpu);
 
-		free_page((unsigned long)hv_cpu->synic_event_page);
-		free_page((unsigned long)hv_cpu->synic_message_page);
+		if (!hv_isolation_type_snp() && !hv_root_partition) {
+			free_page((unsigned long)hv_cpu->synic_event_page);
+			free_page((unsigned long)hv_cpu->synic_message_page);
+		}
 		free_page((unsigned long)hv_cpu->post_msg_page);
 	}
 
-- 
2.25.1