From: Sean Christopherson <seanjc@google.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Ross Philipson <ross.philipson@oracle.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
linux-integrity@vger.kernel.org, linux-doc@vger.kernel.org,
linux-crypto@vger.kernel.org, kexec@lists.infradead.org,
linux-efi@vger.kernel.org, iommu@lists.linux.dev,
dpsmith@apertussolutions.com, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, hpa@zytor.com,
dave.hansen@linux.intel.com, ardb@kernel.org,
mjg59@srcf.ucam.org, James.Bottomley@hansenpartnership.com,
peterhuewe@gmx.de, jarkko@kernel.org, jgg@ziepe.ca,
luto@amacapital.net, nivedita@alum.mit.edu,
herbert@gondor.apana.org.au, davem@davemloft.net,
corbet@lwn.net, ebiederm@xmission.com, dwmw2@infradead.org,
baolu.lu@linux.intel.com, kanth.ghatraju@oracle.com,
trenchboot-devel@googlegroups.com
Subject: Re: [PATCH v13 09/19] x86: Secure Launch kernel early boot stub
Date: Tue, 15 Apr 2025 15:15:21 -0700 [thread overview]
Message-ID: <Z_7aeWAxBSdU6cvc@google.com> (raw)
In-Reply-To: <e781cabc-90ee-48cf-9a09-116a8edace1e@citrix.com>
On Tue, Apr 15, 2025, Andrew Cooper wrote:
> On 11/04/2025 10:40 pm, Sean Christopherson wrote:
> > On Thu, Apr 10, 2025, Ross Philipson wrote:
> >> + * instruction can return for a number of reasons. Test to see if it returned
> >> + * because the monitor was written to.
> >> + */
> >> + monitor
> >> +
> >> +1:
> >> + mfence
> >> + mwait
> >> + movl (%eax), %edx
> > Why load the value into EDX? At a glance, the value is never consumed.
> >
> >> + testl %edx, %edx
> >> + jz 1b
> > This usage of MONITOR/MWAIT is flawed. The monitor needs to be re-armed in each
> > loop, otherwise mwait will be a glorified nop.
> >
> > More importantly, the exit condition needs to be checked before monitor,
>
> after monitor and before mwait.
Gah, yeah, I mean to say "before mwait".
next prev parent reply other threads:[~2025-04-15 22:15 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-10 20:41 [PATCH v13 00/19] x86: Trenchboot secure dynamic launch Linux kernel support Ross Philipson
2025-04-10 20:41 ` [PATCH v13 01/19] Documentation/x86: Secure Launch kernel documentation Ross Philipson
2025-04-11 5:50 ` ALOK TIWARI
2025-04-11 19:41 ` ross.philipson
2025-04-11 21:32 ` Sean Christopherson
2025-04-15 20:44 ` ross.philipson
2025-04-12 16:07 ` ALOK TIWARI
2025-04-15 20:59 ` ross.philipson
2025-04-10 20:41 ` [PATCH v13 02/19] x86: Secure Launch Kconfig Ross Philipson
2025-04-10 20:41 ` [PATCH v13 03/19] x86: Secure Launch Resource Table header file Ross Philipson
2025-04-10 20:41 ` [PATCH v13 04/19] x86: Secure Launch main " Ross Philipson
2025-04-12 18:34 ` ALOK TIWARI
2025-04-15 21:04 ` ross.philipson
2025-04-10 20:41 ` [PATCH v13 05/19] x86: Add early SHA-1 support for Secure Launch early measurements Ross Philipson
2025-04-10 20:41 ` [PATCH v13 06/19] x86: Add early SHA-256 " Ross Philipson
2025-04-10 20:41 ` [PATCH v13 07/19] x86/msr: Add variable MTRR base/mask and x2apic ID registers Ross Philipson
2025-04-10 20:41 ` [PATCH v13 08/19] x86/boot: Place TXT MLE header in the kernel_info section Ross Philipson
2025-04-10 20:41 ` [PATCH v13 09/19] x86: Secure Launch kernel early boot stub Ross Philipson
2025-04-11 21:40 ` Sean Christopherson
2025-04-15 22:12 ` Andrew Cooper
2025-04-15 22:15 ` Sean Christopherson [this message]
2025-04-15 22:16 ` ross.philipson
2025-04-10 20:41 ` [PATCH v13 10/19] x86: Secure Launch kernel late " Ross Philipson
2025-04-10 20:41 ` [PATCH v13 11/19] x86: Secure Launch SMP bringup support Ross Philipson
2025-04-10 20:41 ` [PATCH v13 12/19] kexec: Secure Launch kexec SEXIT support Ross Philipson
2025-04-10 20:41 ` [PATCH v13 13/19] x86/reboot: Secure Launch SEXIT support on reboot paths Ross Philipson
2025-04-10 20:41 ` [PATCH v13 14/19] tpm, tpm_tis: Close all localities Ross Philipson
2025-04-10 20:41 ` [PATCH v13 15/19] tpm, tpm_tis: Address positive localities in tpm_tis_request_locality() Ross Philipson
2025-04-10 20:41 ` [PATCH v13 16/19] tpm, tpm_tis: Allow locality to be set to a different value Ross Philipson
2025-04-12 19:15 ` ALOK TIWARI
2025-04-15 21:04 ` ross.philipson
2025-04-10 20:41 ` [PATCH v13 17/19] tpm, sysfs: Show locality used by kernel Ross Philipson
2025-04-10 20:41 ` [PATCH v13 18/19] x86: Secure Launch late initcall platform module Ross Philipson
2025-04-10 20:41 ` [PATCH v13 19/19] x86/efi: EFI stub DRTM launch support for Secure Launch Ross Philipson
-- strict thread matches above, loose matches on Subject: below --
2025-03-28 23:07 [PATCH v13 00/19] x86: Trenchboot secure dynamic launch Linux kernel support Ross Philipson
2025-03-28 23:08 ` [PATCH v13 09/19] x86: Secure Launch kernel early boot stub Ross Philipson
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