On Monday 22 March 2010 17:06:42 Gui Jianfeng wrote:
> According to SDM, we need to configure EPT paging-structure memory type
> by consulting IA32_VMX_EPT_VPID_CAP.
>
> Signed-off-by: Gui Jianfeng <guijianfeng@xxxxxxxxxxxxxx>
> ---
> arch/x86/include/asm/vmx.h | 2 ++
> arch/x86/kvm/vmx.c | 12 +++++++++---
> 2 files changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
> index fb9a080..1b33a60 100644
> --- a/arch/x86/include/asm/vmx.h
> +++ b/arch/x86/include/asm/vmx.h
> @@ -374,6 +374,8 @@ enum vmcs_field {
> #define VMX_EPT_MT_EPTE_SHIFT 3
> #define VMX_EPT_GAW_EPTP_SHIFT 3
> #define VMX_EPT_DEFAULT_MT 0x6ull
> +#define VMX_EPT_MT_WRBACK 0x6ull
> +#define VMX_EPT_MT_UNCACHABLE 0x0ull
> #define VMX_EPT_READABLE_MASK 0x1ull
> #define VMX_EPT_WRITABLE_MASK 0x2ull
> #define VMX_EPT_EXECUTABLE_MASK 0x4ull
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 06108f3..f971b9b 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -1804,9 +1804,15 @@ static u64 construct_eptp(unsigned long root_hpa)
> {
> u64 eptp;
>
> - /* TODO write the value reading from MSR */
> - eptp = VMX_EPT_DEFAULT_MT |
> - VMX_EPT_DEFAULT_GAW << VMX_EPT_GAW_EPTP_SHIFT;
> + if (cpu_has_vmx_eptp_writeback())
> + eptp = VMX_EPT_MT_WRBACK |
> + VMX_EPT_DEFAULT_GAW << VMX_EPT_GAW_EPTP_SHIFT;
I prefer to ensure WB is supported and used as default. Otherwise it would be
a big trouble for memory subsystem(to use UC for all memory). Both WB and UC
EPT memory types are ensured to be support in hardware.
And you can remove VMX_EPT_DEFAULT_MT as well.
--
regards
Yang, Sheng
> + else if (cpu_has_vmx_eptp_uncacheable())
> + eptp = VMX_EPT_MT_UNCACHABLE |
> + VMX_EPT_DEFAULT_GAW << VMX_EPT_GAW_EPTP_SHIFT;
> + else
> + BUG();
> +
> eptp |= (root_hpa & PAGE_MASK);
>
> return eptp;
>
--
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