From: marc.zyngier@arm•com (Marc Zyngier)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v3 14/14] ARM64: KVM: fix big endian issue in access_vm_reg for 32bit guest
Date: Wed, 28 May 2014 15:20:03 +0100 [thread overview]
Message-ID: <5385F093.7020405@arm.com> (raw)
In-Reply-To: <20140528140915.GB38250@lvm>
On 28/05/14 15:09, Christoffer Dall wrote:
> On Wed, May 28, 2014 at 06:56:44AM -0700, Victor Kamensky wrote:
>> On 28 May 2014 02:14, Christoffer Dall <christoffer.dall@linaro•org> wrote:
>>
>> They cannot be separate it is the same data with two ways
>> to access: as 64bit value or low word 32bit value. Typically it is LPAE
>> cp15 memory related registers like TTBR0, as in mcrr, mcr example
>> in my previous response. mcrr will update high and low word values
>> of TTBR0, mcr will update only low word of it.
>>
> You just have to decide whether you want to represent a 64-bit register as
> a concatenation of two u32's or a 32-bit register access as a part
> of the 64-bit register value.
>
> I think the architecture, at least for 32-bit register views on ARMv8,
> defines the 32-bit accesses as a view on the 64-bit register.
Indeed, and that's how KVM implements it.
> You should of course only store those registers once, but instead of
> storing them in an array of u32's you could store the 64-bit wide
> registers in a separate array of u64's. 32-bit accesses to those
> registers would look in the array of u64's for such a value.
>
> I didn't try it out, so not sure how it looks like, just saying it's an
> option worth considering.
I think that's the best idea so far. If the access is 64bit, use the
64bit version of the union (going through the corresponding
vcpu_sys_reg() interface).
This should be a very minimal refactor.
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2014-05-28 14:20 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-13 16:13 [PATCH v3 00/14] ARM/ARM64: KVM: big endian host support Victor Kamensky
2014-05-13 16:13 ` [PATCH v3 01/14] ARM: KVM: switch hypervisor into BE mode in case of BE host Victor Kamensky
2014-05-27 14:23 ` Marc Zyngier
2014-05-13 16:13 ` [PATCH v3 02/14] ARM: KVM: fix vgic V7 assembler code to work in BE image Victor Kamensky
2014-05-27 14:24 ` Marc Zyngier
2014-05-13 16:13 ` [PATCH v3 03/14] ARM: KVM: handle 64bit values passed to mrcc or from mcrr instructions in BE case Victor Kamensky
2014-05-26 15:28 ` Christoffer Dall
2014-05-28 6:09 ` Victor Kamensky
2014-05-27 14:30 ` Marc Zyngier
2014-05-13 16:13 ` [PATCH v3 04/14] ARM: KVM: __kvm_vcpu_run function return result fix " Victor Kamensky
2014-05-27 15:02 ` Marc Zyngier
2014-05-28 6:10 ` Victor Kamensky
2014-05-13 16:13 ` [PATCH v3 05/14] ARM: KVM: vgic mmio should hold data as LE bytes array " Victor Kamensky
2014-05-27 15:07 ` Marc Zyngier
2014-05-13 16:13 ` [PATCH v3 06/14] ARM: KVM: MMIO support BE host running LE code Victor Kamensky
2014-05-27 15:49 ` Marc Zyngier
2014-05-13 16:13 ` [PATCH v3 07/14] ARM: KVM: one_reg coproc set and get BE fixes Victor Kamensky
2014-05-25 19:14 ` Christoffer Dall
2014-05-28 6:19 ` Victor Kamensky
2014-05-28 8:03 ` Christoffer Dall
2014-05-27 18:22 ` Marc Zyngier
2014-05-28 6:23 ` Victor Kamensky
2014-05-13 16:14 ` [PATCH v3 08/14] ARM: KVM: enable KVM in Kconfig on big-endian systems Victor Kamensky
2014-05-13 16:14 ` [PATCH v3 09/14] ARM64: KVM: MMIO support BE host running LE code Victor Kamensky
2014-05-27 18:25 ` Marc Zyngier
2014-05-13 16:14 ` [PATCH v3 10/14] ARM64: KVM: store kvm_vcpu_fault_info est_el2 as word Victor Kamensky
2014-05-27 18:34 ` Marc Zyngier
2014-05-13 16:14 ` [PATCH v3 11/14] ARM64: KVM: fix vgic_bitmap_get_reg function for BE 64bit case Victor Kamensky
2014-05-26 15:49 ` Christoffer Dall
2014-05-13 16:14 ` [PATCH v3 12/14] ARM64: KVM: vgic_elrsr and vgic_eisr need to be byteswapped in BE case Victor Kamensky
2014-05-26 17:35 ` Christoffer Dall
2014-05-27 19:11 ` Marc Zyngier
2014-05-13 16:14 ` [PATCH v3 13/14] ARM64: KVM: set and get of sys registers " Victor Kamensky
2014-05-14 8:45 ` Marc Zyngier
2014-05-14 14:18 ` Victor Kamensky
2014-05-25 18:26 ` Christoffer Dall
2014-05-13 16:14 ` [PATCH v3 14/14] ARM64: KVM: fix big endian issue in access_vm_reg for 32bit guest Victor Kamensky
2014-05-26 17:52 ` Christoffer Dall
2014-05-28 6:11 ` Victor Kamensky
2014-05-28 9:14 ` Christoffer Dall
2014-05-28 13:56 ` Victor Kamensky
2014-05-28 14:09 ` Christoffer Dall
2014-05-28 14:20 ` Marc Zyngier [this message]
2014-05-26 15:49 ` [PATCH v3 00/14] ARM/ARM64: KVM: big endian host support Christoffer Dall
2014-05-28 6:31 ` Victor Kamensky
2014-05-28 8:12 ` Christoffer Dall
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