From: "Kuppuswamy, Sathyanarayanan" <sathyanarayanan.kuppuswamy@linux.intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>, Peter H Anvin <hpa@zytor.com>,
Dave Hansen <dave.hansen@intel.com>,
Tony Luck <tony.luck@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Andi Kleen <ak@linux.intel.com>,
Kirill Shutemov <kirill.shutemov@linux.intel.com>,
Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
Sean Christopherson <seanjc@google.com>,
linux-kernel@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH v1 05/11] x86/tdx: Add __tdx_module_call() and __tdx_hypercall() helper functions
Date: Mon, 14 Jun 2021 14:37:32 -0700 [thread overview]
Message-ID: <ba91c178-406f-834c-e49c-06fa1d953971@linux.intel.com> (raw)
In-Reply-To: <YMe34ptb8CCV7Vg9@zn.tnic>
On 6/14/21 1:11 PM, Borislav Petkov wrote:
> On Mon, Jun 14, 2021 at 12:45:45PM -0700, Kuppuswamy, Sathyanarayanan wrote:
>> May be I should define a macro for it and use Mov to keep it uniform
>> with other register updates.
>
> Macro?
>
> There's the, well, *MOV* instruction, if you insist on keeping it
> uniform. But this is not about keeping it uniform - it is about having
> the code as clear as understandable as possible:
>
>
> /* Set RAX to TDCALL leaf function 0 */
> xor %eax, %eax
>
> Plain and simple and clear why the XORing is done.
Ok. I will fix the comment.
>> With the trace support, they should be able to see the flow before making
>> the tdx_*_call(). That should be enough clue for debug right?
>
> Are you expecting all those cloud users to trace their guests just to
> figure that out? I'm sceptical they will...
>
> Rather, I'd try to allocate a special error value that
> do_tdx_hypercall() returns in %eax and then have the wrapper which will
> puts %r10 on the stack, check that error value and panic with a nice
> error message.
>
I will add r10 to struct tdx_hypercall_output and return it to callers to
check it.
>
> Btw, where is that function used? Gurgling, it shows it in some MMIO
> patch, I'm guessing that's still coming.
>
> As to how to do it properly, you pass in
>
> struct tdx_hypercall_output *out
>
> as a function parameter and caller can pick out whatever it wants from
> that struct.
It looks like it is used only in MMIO use case now. I think we don't need
it anymore. I will remove it.
>
> Thx.
>
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer
next prev parent reply other threads:[~2021-06-14 21:37 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-02 2:21 [PATCH v1 00/11] Add TDX Guest Support (Initial support) Kuppuswamy Sathyanarayanan
2021-06-02 2:21 ` [PATCH v1 01/11] x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT Kuppuswamy Sathyanarayanan
2021-06-02 2:21 ` [PATCH v1 02/11] x86/tdx: Introduce INTEL_TDX_GUEST config option Kuppuswamy Sathyanarayanan
2021-06-02 2:21 ` [PATCH v1 03/11] x86/cpufeatures: Add TDX Guest CPU feature Kuppuswamy Sathyanarayanan
2021-06-07 14:32 ` Tom Lendacky
2021-06-07 16:59 ` Kuppuswamy, Sathyanarayanan
2021-06-10 12:28 ` Borislav Petkov
2021-06-10 14:28 ` Kuppuswamy, Sathyanarayanan
2021-06-10 14:29 ` Kirill A. Shutemov
2021-06-10 14:35 ` Borislav Petkov
2021-06-10 14:41 ` Kirill A. Shutemov
2021-06-10 15:56 ` Borislav Petkov
2021-06-12 21:02 ` [PATCH v2 03/12] " Kuppuswamy Sathyanarayanan
2021-06-16 9:52 ` Borislav Petkov
2021-06-16 16:57 ` Kuppuswamy, Sathyanarayanan
2021-06-02 2:21 ` [PATCH v1 04/11] x86/x86: Add is_tdx_guest() interface Kuppuswamy Sathyanarayanan
2021-06-10 19:59 ` Borislav Petkov
2021-06-10 21:01 ` Kuppuswamy, Sathyanarayanan
2021-06-10 21:07 ` Borislav Petkov
2021-06-12 21:04 ` [PATCH v2 04/12] x86/x86: Add early_is_tdx_guest() interface Kuppuswamy Sathyanarayanan
2021-06-17 17:05 ` Borislav Petkov
2021-06-18 19:14 ` Kuppuswamy, Sathyanarayanan
2021-06-02 2:21 ` [PATCH v1 05/11] x86/tdx: Add __tdx_module_call() and __tdx_hypercall() helper functions Kuppuswamy Sathyanarayanan
2021-06-14 8:47 ` Borislav Petkov
2021-06-14 19:45 ` Kuppuswamy, Sathyanarayanan
2021-06-14 20:11 ` Borislav Petkov
2021-06-14 21:37 ` Kuppuswamy, Sathyanarayanan [this message]
2021-06-02 2:21 ` [PATCH v1 06/11] x86/tdx: Get TD execution environment information via TDINFO Kuppuswamy Sathyanarayanan
2021-06-02 2:21 ` [PATCH v1 07/11] x86/traps: Add #VE support for TDX guest Kuppuswamy Sathyanarayanan
2021-06-02 2:21 ` [PATCH v1 08/11] x86/tdx: Add HLT " Kuppuswamy Sathyanarayanan
2021-06-02 2:21 ` [PATCH v1 09/11] x86/tdx: Wire up KVM hypercalls Kuppuswamy Sathyanarayanan
2021-06-12 21:08 ` [PATCH v2 10/12] " Kuppuswamy Sathyanarayanan
2021-06-02 2:21 ` [PATCH v1 10/11] x86/tdx: Add MSR support for TDX guest Kuppuswamy Sathyanarayanan
2021-06-02 2:21 ` [PATCH v1 11/11] x86/tdx: Handle CPUID via #VE Kuppuswamy Sathyanarayanan
-- strict thread matches above, loose matches on Subject: below --
2021-06-02 2:18 [PATCH v1 00/11] Add TDX Guest Support (Initial support) Kuppuswamy Sathyanarayanan
2021-06-02 2:18 ` [PATCH v1 05/11] x86/tdx: Add __tdx_module_call() and __tdx_hypercall() helper functions Kuppuswamy Sathyanarayanan
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