linux-kernel - Re: [kvm-devel] include files for kvmclock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4731BAB2.9040004@redhat.com>
Date:	Wed, 07 Nov 2007 11:16:34 -0200
From:	Glauber de Oliveira Costa <gcosta@...hat.com>
To:	Akio Takebe <takebe_akio@...fujitsu.com>
CC:	linux-kernel@...r.kernel.org, jeremy@...p.org, hollisb@...ibm.com,
	kvm-devel@...ts.sourceforge.net, avi@...ranet.com
Subject: Re: [kvm-devel] include files for kvmclock

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Akio Takebe escreveu:
> Hi, Glauber
> 
> This is interesting facility. :-)
> 
>> +#define KVM_HCALL_REGISTER_CLOCK	1
>> +
>> +union kvm_hv_clock {
>> +	struct {
>> +		u64 tsc_mult;
>> +		u64 now_ns;
>> +		/* That's the wall clock, not the water closet */
>> +		u64 wc_sec;
>> +		u64 wc_nsec;
>> +		u64 last_tsc;
>> +		/* At first, we could use the tsc value as a marker, but Jeremy
>> +		 * well noted that it will cause us locking problems in 32-bit
>> +		 * sys, so we have a special version field */
>> +		u32 version;
>> +	};
>> +	char page_align[PAGE_SIZE];
>> +};
>> +
> Why does kvm_hv_clock need page_align?
Each vcpu will register a page on its own. In the guest side, it will be
an array of pages. So, we make it page sized.

> And also the kvm_hv_clock is alloced with kvm_vcpu,
There's no requirements on the host part at all. So it doesn't really
matter. In the next version, I may make it even a simple pointer.

> so the align is not enough, isn't it?
> I thik __atribute__((__aligne__(PAGE_SIZE)))) is better than it.
It deals with the start of the structure, but not with its size. See the
guest part: Where it matters, I do use it.


Thanks

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.7 (GNU/Linux)
Comment: Using GnuPG with Remi - http://enigmail.mozdev.org

iD8DBQFHMbqyjYI8LaFUWXMRAgfOAKCTeKF3cWbhILYSXY+MjtXo8B87EwCeNNhn
z9RDYaCWHIxsqlciMF0i27w=
=EIEM
-----END PGP SIGNATURE-----
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/