From: Dave Hansen <dave.hansen@intel.com>
To: Kai Huang <kai.huang@intel.com>,
bp@alien8.de, tglx@linutronix.de, peterz@infradead.org,
mingo@redhat.com
Cc: kirill.shutemov@linux.intel.com, hpa@zytor.com, x86@kernel.org,
linux-kernel@vger.kernel.org, pbonzini@redhat.com,
seanjc@google.com, rick.p.edgecombe@intel.com,
reinette.chatre@intel.com, isaku.yamahata@intel.com,
dan.j.williams@intel.com, thomas.lendacky@amd.com,
ashish.kalra@amd.com, nik.borisov@suse.com, sagis@google.com
Subject: Re: [PATCH v2.1 2/5] x86/virt/tdx: Mark memory cache state incoherent when making SEAMCALL
Date: Wed, 14 May 2025 08:52:20 -0700 [thread overview]
Message-ID: <66f5b7f0-8109-4c10-80ef-783ba8bccae6@intel.com> (raw)
In-Reply-To: <20250514101022.7537-1-kai.huang@intel.com>
On 5/14/25 03:10, Kai Huang wrote:
> Turn on that boolean when the kernel does SEAMCALL so that kexec can
> correctly flush cache. Note not all SEAMCALL leaf functions generate
> dirty cachelines of TDX private memory, but for simplicity, just treat
> all of them do.
It's not just for simplicity.
There's no contract in place for when the TDX module will dirty memory
or not. A call that is "clean" today might dirty memory tomorrow.
The _only_ thing we know is that SEAMCALLs can dirty cachelines. We
don't know when or how they do it. This blurb makes it sound like it's
possible to optimize this. It's not.
next prev parent reply other threads:[~2025-05-14 15:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-10 11:20 [PATCH v2 0/5] TDX host: kexec/kdump support Kai Huang
2025-05-10 11:20 ` [PATCH v2 1/5] x86/sme: Use percpu boolean to control wbinvd during kexec Kai Huang
2025-05-10 11:20 ` [PATCH v2 2/5] x86/virt/tdx: Mark memory cache state incoherent when making SEAMCALL Kai Huang
2025-05-14 10:10 ` [PATCH v2.1 " Kai Huang
2025-05-14 15:52 ` Dave Hansen [this message]
2025-05-14 22:13 ` Huang, Kai
2025-05-10 11:20 ` [PATCH v2 3/5] x86/kexec: Disable kexec/kdump on platforms with TDX partial write erratum Kai Huang
2025-05-10 11:20 ` [PATCH v2 4/5] x86/virt/tdx: Remove the !KEXEC_CORE dependency Kai Huang
2025-05-10 11:20 ` [PATCH v2 5/5] x86/virt/tdx: Update the kexec section in the TDX documentation Kai Huang
2025-05-10 11:25 ` [RFC PATCH v2 6/5] KVM: TDX: Explicitly do WBINVD upon reboot notifier Kai Huang
2025-06-13 11:36 ` Paolo Bonzini
2025-06-16 10:39 ` Huang, Kai
2025-05-14 12:37 ` [PATCH v2 0/5] TDX host: kexec/kdump support Tom Lendacky
2025-05-14 22:09 ` Huang, Kai
2025-05-29 11:06 ` Huang, Kai
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=66f5b7f0-8109-4c10-80ef-783ba8bccae6@intel.com \
--to=dave.hansen@intel.com \
--cc=ashish.kalra@amd.com \
--cc=bp@alien8.de \
--cc=dan.j.williams@intel.com \
--cc=hpa@zytor.com \
--cc=isaku.yamahata@intel.com \
--cc=kai.huang@intel.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=nik.borisov@suse.com \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=reinette.chatre@intel.com \
--cc=rick.p.edgecombe@intel.com \
--cc=sagis@google.com \
--cc=seanjc@google.com \
--cc=tglx@linutronix.de \
--cc=thomas.lendacky@amd.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®