Re: [PATCH 2/2] kvm-unit-test nVMX: Test Host Segment Registers and Descriptor Tables on vmentry of nested guests

From: Nadav Amit <nadav.amit@gmail.com>
To: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Cc: kvm@vger.kernel.org, rkrcmar@redhat.com, pbonzini@redhat.com,
	jmattson@google.com
Subject: Re: [PATCH 2/2] kvm-unit-test nVMX: Test Host Segment Registers and Descriptor Tables on vmentry of nested guests
Date: Fri, 28 Jun 2019 19:00:00 -0700	[thread overview]
Message-ID: <5F6321E0-0F9F-464B-B20B-2A6669C7C76E@gmail.com> (raw)
In-Reply-To: <20190628221447.23498-3-krish.sadhukhan@oracle.com>

> On Jun 28, 2019, at 3:14 PM, Krish Sadhukhan <krish.sadhukhan@oracle.com> wrote:
> 
> According to section "Checks on Host Segment and Descriptor-Table
> Registers" in Intel SDM vol 3C, the following checks are performed on
> vmentry of nested guests:
> 
>    - In the selector field for each of CS, SS, DS, ES, FS, GS and TR, the
>      RPL (bits 1:0) and the TI flag (bit 2) must be 0.
>    - The selector fields for CS and TR cannot be 0000H.
>    - The selector field for SS cannot be 0000H if the "host address-space
>      size" VM-exit control is 0.
>    - On processors that support Intel 64 architecture, the base-address
>      fields for FS, GS, GDTR, IDTR, and TR must contain canonical
>      addresses.
> 
> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
> Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
> ---
> lib/x86/processor.h |   5 ++
> x86/vmx_tests.c     | 159 ++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 164 insertions(+)
> 
> diff --git a/lib/x86/processor.h b/lib/x86/processor.h
> index 4fef0bc..c6edc26 100644
> --- a/lib/x86/processor.h
> +++ b/lib/x86/processor.h
> @@ -461,6 +461,11 @@ static inline void write_pkru(u32 pkru)
>         : : "a" (eax), "c" (ecx), "d" (edx));
> }
> 
> +static u64 make_non_canonical(u64 addr)
> +{
> +	return (addr | 1ull << 48);
> +}

You may wan to make it “static inline”. On my system I get:

processor.h:464:12: error: ‘make_non_canonical’ defined but not used [-Werror=unused-function]