[PATCH 1/6] kvm: pass error code to handler

[PATCH 1/6] kvm: pass error code to handler

[Lai Jiangshan]

handle_ept_violation() does not pass error code to
the handler tdp_page_fault().

It means tdp_page_fault() handles the page fault with ignoring
the error code, It will not handle the page fault completely correctly,
and may causes endless page fault.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 856e427..b40731e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3521,7 +3521,8 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu)
 
 	gpa = vmcs_read64(GUEST_PHYSICAL_ADDRESS);
 	trace_kvm_page_fault(gpa, exit_qualification);
-	return kvm_mmu_page_fault(vcpu, gpa & PAGE_MASK, 0);
+	return kvm_mmu_page_fault(vcpu, gpa & PAGE_MASK,
+			exit_qualification & 0x2);
 }
 
 static u64 ept_rsvd_mask(u64 spte, int level)

Re: [PATCH 1/6] kvm: pass error code to handler

[Avi Kivity]

On 07/16/2010 05:12 AM, Lai Jiangshan wrote:
> handle_ept_violation() does not pass error code to
> the handler tdp_page_fault().
>
> It means tdp_page_fault() handles the page fault with ignoring
> the error code, It will not handle the page fault completely correctly,
> and may causes endless page fault.
>
>    

Please describe the fail scenario more accurately in the change log?

Can it happen now, or only with the next patches in the series?

> @@ -3521,7 +3521,8 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu)
>
>   	gpa = vmcs_read64(GUEST_PHYSICAL_ADDRESS);
>   	trace_kvm_page_fault(gpa, exit_qualification);
> -	return kvm_mmu_page_fault(vcpu, gpa&  PAGE_MASK, 0);
> +	return kvm_mmu_page_fault(vcpu, gpa&  PAGE_MASK,
> +			exit_qualification&  0x2);
>   }
>
>    

Symbolic constant please.

I don't really like how kvm_mmu_page_fault() is overloaded, for !tdp the 
parameter is a gva, for tdp it is a gpa.  We need to break it into two 
(but later).

-- 
error compiling committee.c: too many arguments to function