Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <03f62671-7f01-eeb3-4326-cbf0c2250c30@linux.microsoft.com>
Date:   Tue, 4 Apr 2023 16:09:12 +0530
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.9.1
Subject: Re: [PATCH] Drivers: hv: Do not free synic pages when they were not
 allocated
To:     Nuno Das Neves <nunodasneves@linux.microsoft.com>,
        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
References: <1680564122-30819-1-git-send-email-nunodasneves@linux.microsoft.com>
Content-Language: en-US
From:   Jinank Jain <jinankjain@linux.microsoft.com>
In-Reply-To: <1680564122-30819-1-git-send-email-nunodasneves@linux.microsoft.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

Reviewed-by: Jinank Jain <jinankjain@linux.microsoft.com>

On 4/4/2023 4:52 AM, Nuno Das Neves wrote:
> 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);
>   	}
>