From: Peter Zijlstra <peterz@infradead.org>
To: Kairui Song <kasong@redhat.com>
Cc: linux-kernel@vger.kernel.org,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Sasha Levin <sashal@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Dave Young <dyoung@redhat.com>,
x86@kernel.org, devel@linuxdriverproject.org
Subject: Re: [RFC PATCH] x86, hyperv: fix kernel panic when kexec on HyperV VM
Date: Wed, 27 Feb 2019 13:01:41 +0100 [thread overview]
Message-ID: <20190227120141.GN32494@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190226155615.16724-1-kasong@redhat.com>
On Tue, Feb 26, 2019 at 11:56:15PM +0800, Kairui Song wrote:
> arch/x86/hyperv/hv_init.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> index 7abb09e2eeb8..92291c18d716 100644
> --- a/arch/x86/hyperv/hv_init.c
> +++ b/arch/x86/hyperv/hv_init.c
> @@ -406,6 +406,10 @@ void hyperv_cleanup(void)
> /* Reset our OS id */
> wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
>
> + /* Cleanup page reference before reset the page */
> + hv_hypercall_pg = NULL;
> + wmb();
What do we need that SFENCE for? Any why does it lack a comment?
> +
> /* Reset the hypercall page */
> hypercall_msr.as_uint64 = 0;
> wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
> --
> 2.20.1
>
next prev parent reply other threads:[~2019-02-27 12:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-26 15:56 [RFC PATCH] x86, hyperv: fix kernel panic when kexec on HyperV VM Kairui Song
2019-02-26 16:39 ` Vitaly Kuznetsov
2019-02-27 12:01 ` Peter Zijlstra [this message]
2019-02-27 14:55 ` Kairui Song
2019-03-05 12:28 ` Peter Zijlstra
2019-03-05 13:32 ` Kairui Song
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