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From: "Nicholas Piggin" <npiggin@gmail.com>
To: "Harsh Prateek Bora" <harshpb@linux.ibm.com>, <qemu-ppc@nongnu.org>
Cc: "Caleb Schlossin" <calebs@linux.vnet.ibm.com>,
	"Cédric Le Goater" <clg@kaod.org>,
	"Frédéric Barrat" <fbarrat@linux.ibm.com>,
	"Daniel Henrique Barboza" <danielhb413@gmail.com>,
	qemu-devel@nongnu.org
Subject: Re: [RFC PATCH 06/10] ppc: Add a core_index to CPUPPCState for SMT vCPUs
Date: Wed, 29 May 2024 10:28:32 +1000	[thread overview]
Message-ID: <D1LPBPFH9DL7.2ZXX9I94PCZUB@gmail.com> (raw)
In-Reply-To: <e18f4a73-055c-4fc9-bad8-26a9a70fe081@linux.ibm.com>

On Tue May 28, 2024 at 6:52 PM AEST, Harsh Prateek Bora wrote:
> corrected typo, it's bitwise.
>
> On 5/28/24 14:18, Harsh Prateek Bora wrote:
> >> -    (POWERPC_CPU(cs)->env.spr_cb[SPR_PIR].default_value & 
> >> ~(cs->nr_threads - 1))
> >> +    (POWERPC_CPU(cs)->env.core_index)
> > 
> > Dont we want to keep the bitwise & with ~(cs->nr_threads - 1) ?
> > How's it taken care ?

For these accessors it actually just wants to have something that
compares if a CPU belongs to the same core or not, so exact value
doesn't really matter.

Maybe the helpers should do that comparison. It could possibly even
be a class method to be really clean, although that's more costly
to call (but writing to a SMT shared register is pretty costly anyway
so maybe doesn't matter).

I'll think a bit more.

Thanks,
Nick


  reply	other threads:[~2024-05-29  0:29 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-26 12:26 [RFC PATCH 00/10] ppc/pnv: Better big-core model, lpar-per-core, PC unit Nicholas Piggin
2024-05-26 12:26 ` [RFC PATCH 01/10] ppc/pnv: Add pointer from PnvCPUState to PnvCore Nicholas Piggin
2024-05-27 15:23   ` Cédric Le Goater
2024-05-28  6:19   ` Harsh Prateek Bora
2024-05-26 12:26 ` [RFC PATCH 02/10] ppc/pnv: Move timebase state into PnvCore Nicholas Piggin
2024-05-28  6:28   ` Harsh Prateek Bora
2024-05-28  7:52     ` Cédric Le Goater
2024-05-29  0:19       ` Nicholas Piggin
2024-05-26 12:26 ` [RFC PATCH 03/10] target/ppc: Improve SPR indirect registers Nicholas Piggin
2024-05-28  6:50   ` Harsh Prateek Bora
2024-05-29  0:13     ` Nicholas Piggin
2024-05-26 12:26 ` [RFC PATCH 04/10] ppc/pnv: specialise init for powernv8/9/10 machines Nicholas Piggin
2024-05-28  7:10   ` Harsh Prateek Bora
2024-05-28  7:45     ` Cédric Le Goater
2024-05-29  0:18       ` Nicholas Piggin
2024-05-26 12:26 ` [RFC PATCH 05/10] ppc/pnv: Extend chip_pir class method to TIR as well Nicholas Piggin
2024-05-28  8:32   ` Harsh Prateek Bora
2024-05-29  0:24     ` Nicholas Piggin
2024-05-29  6:30       ` Cédric Le Goater
2024-05-30  6:38         ` Nicholas Piggin
2024-05-30  6:42           ` Cédric Le Goater
2024-05-26 12:26 ` [RFC PATCH 06/10] ppc: Add a core_index to CPUPPCState for SMT vCPUs Nicholas Piggin
2024-05-28  8:48   ` Harsh Prateek Bora
2024-05-28  8:52     ` Harsh Prateek Bora
2024-05-29  0:28       ` Nicholas Piggin [this message]
2024-05-26 12:26 ` [RFC PATCH 07/10] target/ppc: Add helpers to check for SMT sibling threads Nicholas Piggin
2024-05-28  9:16   ` Harsh Prateek Bora
2024-05-29  0:31     ` Nicholas Piggin
2024-05-29  6:34   ` Cédric Le Goater
2024-05-30  6:38     ` Nicholas Piggin
2024-05-26 12:26 ` [RFC PATCH 08/10] ppc/pnv: Invert the design for big-core machine modelling Nicholas Piggin
2024-05-29  6:57   ` Cédric Le Goater
2024-05-30  6:52     ` Nicholas Piggin
2024-05-30  7:46       ` Cédric Le Goater
2024-06-03  5:22         ` Nicholas Piggin
2024-05-29 10:49   ` Harsh Prateek Bora
2024-05-26 12:26 ` [RFC PATCH 09/10] ppc/pnv: Implement POWER10 PC xscom registers for direct controls Nicholas Piggin
2024-05-29  7:00   ` Cédric Le Goater
2024-05-30  6:53     ` Nicholas Piggin
2024-05-26 12:26 ` [RFC PATCH 10/10] ppc/pnv: Add an LPAR per core machine option Nicholas Piggin
2024-05-29  7:02   ` Cédric Le Goater
2024-05-27  6:25 ` [RFC PATCH 00/10] ppc/pnv: Better big-core model, lpar-per-core, PC unit Cédric Le Goater
2024-05-27  7:32   ` Nicholas Piggin
2024-05-27  7:36     ` Cédric Le Goater

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