From: Gleb Natapov <gleb@redhat.com>
To: David Daney <ddaney@caviumnetworks.com>
Cc: David Daney <ddaney.cavm@gmail.com>,
linux-mips@linux-mips.org, ralf@linux-mips.org,
kvm@vger.kernel.org, Sanjay Lal <sanjayl@kymasys.com>,
linux-kernel@vger.kernel.org,
David Daney <david.daney@cavium.com>
Subject: Re: [PATCH v3 5/5] mips/kvm: Fix ABI by moving manipulation of CP0 registers to KVM_{G,S}ET_MSRS
Date: Tue, 21 May 2013 19:28:11 +0300 [thread overview]
Message-ID: <20130521162811.GE14287@redhat.com> (raw)
In-Reply-To: <519B9EF2.8020107@caviumnetworks.com>
On Tue, May 21, 2013 at 09:21:06AM -0700, David Daney wrote:
> On 05/21/2013 08:37 AM, Gleb Natapov wrote:
> >On Mon, May 20, 2013 at 02:01:26PM -0700, David Daney wrote:
> >>From: David Daney <david.daney@cavium.com>
> >>
> >>Because not all 256 CP0 registers are ever implemented, we need a
> >>different method of manipulating them. Use the
> >>KVM_GET_MSRS/KVM_SET_MSRS mechanism as x86 does for its MSRs.
> >>
> >Have you looked at KVM_(GET|SET)_ONE_REG interface (not used by x86, but is
> >used bu arm/ppc/s390). It looks like it is more suitable for your case.
> >Actually you can use it instead of KVM_(GET|SET)_REGS for all registers.
>
> Yes, I suppose it could be used. One problem it has is that there
> is no way to query the set of supported registers.
KVM_GET_REG_LIST
> Also you have to
> make multiple calls to set multiple registers, which involves
> vcpu_{load,put} for each register.
>
How often this happens on the fast path on mips? On x86 this never
happens on the fast path so it uses KVM_(GET|SET)_REGS mostly for
historical reasons.
> We will definitely implement it for all the FP and General Purpose
> registers.
>
> >
> >>Code related to implementing KVM_GET_MSRS/KVM_SET_MSRS is consolidated
>
--
Gleb.
next prev parent reply other threads:[~2013-05-21 16:28 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-20 21:01 [PATCH v3 0/5] mips/kvm: Fix ABI for compatibility with 64-bit guests David Daney
2013-05-20 21:01 ` [PATCH v3 1/5] mips/kvm: Fix ABI for use of FPU David Daney
2013-05-20 21:01 ` [PATCH v3 2/5] mips/kvm: Fix ABI for use of 64-bit registers David Daney
2013-05-20 21:01 ` [PATCH v3 3/5] mips/kvm: Fix name of gpr field in struct kvm_regs David Daney
2013-05-20 21:01 ` [PATCH v3 4/5] mips/kvm: Use ARRAY_SIZE() instead of hardcoded constants in kvm_arch_vcpu_ioctl_{s,g}et_regs David Daney
2013-05-20 21:01 ` [PATCH v3 5/5] mips/kvm: Fix ABI by moving manipulation of CP0 registers to KVM_{G,S}ET_MSRS David Daney
2013-05-21 15:37 ` Gleb Natapov
2013-05-21 16:21 ` David Daney
2013-05-21 16:28 ` Gleb Natapov [this message]
2013-05-21 16:34 ` David Daney
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