linux-kernel - Re: [PATCHv2 01/12] x86/tdx: Consolidate TDX error handling

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Message-ID: <aFxpuRLYA2L6Qfsi@google.com>
Date: Wed, 25 Jun 2025 14:27:21 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Rick P Edgecombe <rick.p.edgecombe@...el.com>
Cc: "kirill.shutemov@...ux.intel.com" <kirill.shutemov@...ux.intel.com>, 
	"pbonzini@...hat.com" <pbonzini@...hat.com>, Dave Hansen <dave.hansen@...el.com>, 
	"dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>, Chao Gao <chao.gao@...el.com>, 
	"bp@...en8.de" <bp@...en8.de>, Kai Huang <kai.huang@...el.com>, "x86@...nel.org" <x86@...nel.org>, 
	"mingo@...hat.com" <mingo@...hat.com>, Yan Y Zhao <yan.y.zhao@...el.com>, 
	"tglx@...utronix.de" <tglx@...utronix.de>, "kvm@...r.kernel.org" <kvm@...r.kernel.org>, 
	"linux-coco@...ts.linux.dev" <linux-coco@...ts.linux.dev>, Isaku Yamahata <isaku.yamahata@...el.com>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCHv2 01/12] x86/tdx: Consolidate TDX error handling

On Wed, Jun 25, 2025, Rick P Edgecombe wrote:
> On Wed, 2025-06-25 at 10:58 -0700, Dave Hansen wrote:
> > > --- a/arch/x86/kvm/vmx/tdx.c
> > > +++ b/arch/x86/kvm/vmx/tdx.c
> > > @@ -202,12 +202,6 @@ static DEFINE_MUTEX(tdx_lock);
> > >   
> > >   static atomic_t nr_configured_hkid;
> > >   
> > > -static bool tdx_operand_busy(u64 err)
> > > -{
> > > -	return (err & TDX_SEAMCALL_STATUS_MASK) == TDX_OPERAND_BUSY;
> > > -}
> > > -
> > > -
> > 
> > Isaku, this one was yours (along with the whitespace damage). What do
> > you think of this patch?
> 
> I think this actually got added by Paolo, suggested by Binbin. I like these
> added helpers a lot. KVM code is often open coded for bitwise stuff, but since
> Paolo added tdx_operand_busy(), I like the idea of following the pattern more
> broadly. I'm on the fence about tdx_status() though.

Can we turn them into macros that make it super obvious they are checking if the
error code *is* xyz?  E.g.

#define IS_TDX_ERR_OPERAND_BUSY
#define IS_TDX_ERR_OPERAND_INVALID
#define IS_TDX_ERR_NO_ENTROPY
#define IS_TDX_ERR_SW_ERROR

As is, it's not at all clear that things like tdx_success() are simply checks,
as opposed to commands.