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Message-ID: <4DF06F5E.9070608@redhat.com>
Date: Thu, 09 Jun 2011 09:59:42 +0300
From: Avi Kivity <avi@...hat.com>
To: Xiao Guangrong <xiaoguangrong@...fujitsu.com>
CC: Marcelo Tosatti <mtosatti@...hat.com>,
LKML <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org>
Subject: Re: [PATCH 03/15] KVM: x86: avoid unnecessarily guest page table
walking
On 06/07/2011 03:59 PM, Xiao Guangrong wrote:
> We already get the guest physical address, so use it to read guest data
> directly to avoid walking guest page table again
>
> Signed-off-by: Xiao Guangrong<xiaoguangrong@...fujitsu.com>
> ---
> arch/x86/kvm/x86.c | 3 +--
> 1 files changed, 1 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 694538a..8be9ff6 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3930,8 +3930,7 @@ static int emulator_read_emulated(struct x86_emulate_ctxt *ctxt,
> if ((gpa& PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
> goto mmio;
>
> - if (kvm_read_guest_virt(ctxt, addr, val, bytes, exception)
> - == X86EMUL_CONTINUE)
> + if (!kvm_read_guest(vcpu->kvm, gpa, val, bytes))
> return X86EMUL_CONTINUE;
This breaks is addr/bytes spans a page boundary.
(the current code is also broken, but only for mmio; the new code is
broken for ram as well).
We need a gva_to_gpa() that returns a range of pages.
--
error compiling committee.c: too many arguments to function
--
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