Re: [PATCH] KVM-Use value reading from MSR when construct the eptp in VMX mode

[Wanpeng Li]

Please Cc kvm ml.
On Sun, Aug 24, 2014 at 11:54:32AM +0800, Dennis Chen wrote:
>This patch is used to construct the eptp in vmx mode with values
>readed from MSR according to the intel x86 software developer's
>manual.
>
>Signed-off-by: Dennis Chen <kernel.org.gnu@xxxxxxxxx>
>---
> arch/x86/include/asm/vmx.h |    1 +
> arch/x86/kvm/vmx.c         |   21 +++++++++++++++++----
> 2 files changed, 18 insertions(+), 4 deletions(-)
>
>diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
>index bcbfade..bf82a77 100644
>--- a/arch/x86/include/asm/vmx.h
>+++ b/arch/x86/include/asm/vmx.h
>@@ -417,6 +417,7 @@ enum vmcs_field {
> #define VMX_EPT_GAW_EPTP_SHIFT            3
> #define VMX_EPT_AD_ENABLE_BIT            (1ull << 6)
> #define VMX_EPT_DEFAULT_MT            0x6ull
>+#define VMX_EPT_UC_MT                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 bfe11cf..7add5ce 100644
>--- a/arch/x86/kvm/vmx.c
>+++ b/arch/x86/kvm/vmx.c
>@@ -3477,11 +3477,24 @@ static void vmx_set_cr0(struct kvm_vcpu *vcpu,
>unsigned long cr0)
>
> static u64 construct_eptp(unsigned long root_hpa)
> {
>-    u64 eptp;
>+    u64 eptp, pwl;
>+
>+    if (cpu_has_vmx_ept_4levels())
>+        pwl = VMX_EPT_DEFAULT_GAW << VMX_EPT_GAW_EPTP_SHIFT;
>+    else {
>+        WARN(1, "Unsupported page-walk length of 4.\n");
>+        BUG();
>+    }
>+
>+    if (cpu_has_vmx_eptp_writeback())
>+        eptp = VMX_EPT_DEFAULT_MT | pwl;
>+    else if (cpu_has_vmx_eptp_uncacheable())
>+        eptp = VMX_EPT_UC_MT | pwl;
>+    else {
>+        WARN(1, "Unsupported memory type config in vmx eptp.\n");
>+        BUG();
>+    }
>
>-    /* TODO write the value reading from MSR */
>-    eptp = VMX_EPT_DEFAULT_MT |
>-        VMX_EPT_DEFAULT_GAW << VMX_EPT_GAW_EPTP_SHIFT;
>     if (enable_ept_ad_bits)
>         eptp |= VMX_EPT_AD_ENABLE_BIT;
>     eptp |= (root_hpa & PAGE_MASK);
>-- 
>1.7.9.5
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