From: Dave Hansen <dave.hansen@intel.com>
To: Sean Christopherson <seanjc@google.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Juergen Gross <jgross@suse.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
linux-coco@lists.linux.dev,
Dave Hansen <dave.hansen@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] x86/kvm/tdx: Save %rbp in TDX_MODULE_CALL
Date: Fri, 17 May 2024 09:34:56 -0700 [thread overview]
Message-ID: <551d2539-91b4-41e1-97e6-701921e83db7@intel.com> (raw)
In-Reply-To: <Zkd28IN8KvyD4GIX@google.com>
On 5/17/24 09:12, Sean Christopherson wrote:
>> There's a feature in TDX module 1.5 that prevents RBP modification across
>> TDH.VP.ENTER SEAMCALL. See NO_RBP_MOD in TDX Module 1.5 ABI spec.
> LOL, "feature". How was clobbering RBP not treated as a bug? I'm party joking,
> but also quite serious.
I'm on the same page. It would have been far simpler for all involved
to retroactively say that modifying RBP is against the rules and any
module that does it is buggy. Get a new module if yours is buggy.
I _believe_ the intent was to support guest/host combinations that used
RBP for whatever reason. But I'm not sure such a combination exists or
ever existed in practice.
next prev parent reply other threads:[~2024-05-17 16:34 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-17 12:14 [PATCH] x86/kvm/tdx: Save %rbp in TDX_MODULE_CALL Juergen Gross
2024-05-17 13:55 ` Kirill A. Shutemov
2024-05-17 14:08 ` Juergen Gross
2024-05-17 14:39 ` Kirill A. Shutemov
2024-05-17 14:41 ` Kirill A. Shutemov
2024-05-17 14:44 ` Juergen Gross
2024-05-17 15:16 ` Dave Hansen
2024-05-17 15:27 ` Jürgen Groß
2024-05-17 15:43 ` Dave Hansen
2024-05-17 15:48 ` Juergen Gross
2024-05-17 15:52 ` Dave Hansen
2024-05-17 15:58 ` Juergen Gross
2024-05-17 16:48 ` Dave Hansen
2024-05-20 11:54 ` Huang, Kai
2024-05-23 5:56 ` Jürgen Groß
2024-05-23 10:30 ` Huang, Kai
2024-05-23 12:26 ` Huang, Kai
2024-05-23 12:43 ` Jürgen Groß
2024-05-23 22:34 ` Huang, Kai
2024-05-23 23:28 ` Huang, Kai
2024-05-24 5:46 ` Jürgen Groß
2024-05-17 16:12 ` Sean Christopherson
2024-05-17 16:34 ` Dave Hansen [this message]
2024-05-17 17:01 ` Kirill A. Shutemov
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