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charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.54.1 (3.54.1-1.fc41) MIME-Version: 1.0 X-Rspamd-Queue-Id: D6A6B1A0004 X-Rspamd-Server: rspam12 X-Stat-Signature: pqukzbbdbxrpeg5yujmxo71drzuwzx6p X-Rspam-User: X-HE-Tag: 1736869688-795712 X-HE-Meta: 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 AI3R25Hc wdSIKqjq4/1H0+8pVxbrapqh4l7/xcf9SO2EebQtHHsUFGmpqdq6rOkHiP4K1wZE1/jUiqLGUwUJjkYtFQ+avtYtcCaCkHsmkHN/sN29zZ3XJABOz03cUUkiT/26non8SD3CeegK69o/dJOgNSANZpytJaW0MN97KlcPTnJBouL8Gok1/qmkz8a4+k19aJM+5GrIrePmFRhAibEvEdOW1nZEyY/+drTP4S3RR31C3pUh0+sOV74PllS3bd3y3RX21l/l6C1COs0beJPULYqYBl6MFa4ABc7wOrvp8CBqesj+Q9+1BQQ2NuZqgcMOJRMIwRvwd9LaJn+mws9JM4xOmASUMng== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 2025-01-14 at 09:23 -0600, Tom Lendacky wrote: > On 1/14/25 09:05, Dave Hansen wrote: > > On 1/14/25 06:29, Tom Lendacky wrote: > > > > Given the choice between "a bug in the calling code > > > > crashes the kernel" and "a bug in the calling code > > > > results in a missed TLB flush", I'm guessing the > > > > crash is probably better. > > > So instead of the negative number protection, shouldn't this just > > > use an > > > unsigned int for extra_count and panic() if the value is greater > > > than > > > invlpgb_count_max? The caller has some sort of logic problem and > > > it > > > could possibly result in missed TLB flushes. Or if a panic() is > > > out of > > > the question, maybe a WARN() and a full TLB flush to be safe? > >=20 > > The current implementation will panic in the #GP handler though. It > > should be pretty easy to figure out that INVLPGB is involved with > > RIP or > > the Code: snippet. From there, you'd need to figure out what caused > > the #GP. >=20 > Hmmm, maybe I'm missing something. IIUC, when a negative number is > supplied, the extra_count field will be set to 0 (via the max() > function) and allow the INVLPGB to continue. 0 is valid in ECX[15:0] > and > so the instruction won't #GP. I added that at the request of somebody else :) Let me remove it again, now that we seem to have a consensus that a panic is preferable to a wrong TLB flush. --=20 All Rights Reversed.