From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Joao Martins <joao.m.martins@oracle.com>,
linux-kernel@vger.kernel.org, xen-devel@lists.xen.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
David Vrabel <david.vrabel@citrix.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org
Subject: Re: [PATCH RFC 2/3] x86/xen/time: setup vcpu 0 time info page
Date: Mon, 4 Jan 2016 16:34:11 -0500 [thread overview]
Message-ID: <568AE553.5030303@oracle.com> (raw)
In-Reply-To: <568AD8F3.2050600@oracle.com>
On 01/04/2016 03:41 PM, Joao Martins wrote:
>
> On 01/04/2016 04:07 PM, Boris Ostrovsky wrote:
>> On 12/28/2015 04:52 PM, Joao Martins wrote:
>>
>>> +
>>> + size = PAGE_ALIGN(sizeof(struct pvclock_vsyscall_time_info));
>>> + mem = memblock_alloc(size, PAGE_SIZE);
>>> + if (!mem)
>>> + return -ENOMEM;
>>> +
>>> + ti = __va(mem);
>>> + memset(ti, 0, size);
>> Can you just use get_zeroed_page()? (struct pvclock_vsyscall_time_info
>> is always less than a page, isn't it?).
> Yeah, I can use get_zeroed_page() (struct pvclock_vsyscall_time_info is always
> less than a page).
>
> Additionally perhaps this region shouldn't be freed if PVCLOCK_TSC_STABLE_BIT
> isn't supported, because otherwise I would end up corrupting data elsewhere
> since the pvti would still be periodically updated by Xen, right?
You could try setting it back to NULL. e.g.
if (!HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area, cpu,
NULL))
free_page(..);
-boris
next prev parent reply other threads:[~2016-01-04 21:34 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-28 21:52 [PATCH RFC 0/3] x86/xen: pvclock vdso support Joao Martins
2015-12-28 21:52 ` [PATCH RFC 1/3] x86/pvclock: add setter for pvclock_pvti_cpu0_va Joao Martins
2015-12-28 23:45 ` Andy Lutomirski
2015-12-28 23:45 ` Andy Lutomirski
2015-12-29 12:50 ` Joao Martins
2015-12-29 12:50 ` Joao Martins
2015-12-29 13:03 ` Andy Lutomirski
2015-12-29 13:03 ` Andy Lutomirski
2015-12-28 21:52 ` Joao Martins
2015-12-28 21:52 ` [PATCH RFC 2/3] x86/xen/time: setup vcpu 0 time info page Joao Martins
2016-01-04 16:07 ` Boris Ostrovsky
2016-01-04 16:07 ` Boris Ostrovsky
2016-01-04 20:41 ` Joao Martins
2016-01-04 20:41 ` Joao Martins
2016-01-04 21:34 ` Boris Ostrovsky
2016-01-04 21:34 ` Boris Ostrovsky [this message]
2016-01-05 12:20 ` Joao Martins
2016-01-05 12:20 ` Joao Martins
2015-12-28 21:52 ` Joao Martins
2015-12-28 21:52 ` [PATCH RFC 3/3] xen/Kconfig: add XEN_TIME_VSYSCALL option Joao Martins
2015-12-28 21:52 ` Joao Martins
2016-01-04 16:12 ` David Vrabel
2016-01-04 16:12 ` [Xen-devel] " David Vrabel
2016-01-04 16:15 ` Boris Ostrovsky
2016-01-04 16:15 ` [Xen-devel] " Boris Ostrovsky
2016-01-04 20:41 ` Joao Martins
2016-01-04 20:41 ` [Xen-devel] " Joao Martins
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