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charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: AB4264000F X-Stat-Signature: mcjbpysu4uqyoe9ztg331g1rfs8wsu7x X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1736188168-401853 X-HE-Meta: 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 q9JNogmr 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000021, 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 Mon, Jan 06, 2025, Jann Horn wrote: > +KVM/SVM folks in case they know more about how enabling CPU features > interacts with virtualization; original patch is at > https://lore.kernel.org/all/20241230175550.4046587-12-riel@surriel.com/ >=20 > On Sat, Jan 4, 2025 at 4:08=E2=80=AFAM Rik van Riel wr= ote: > > On Fri, 2025-01-03 at 18:49 +0100, Jann Horn wrote: > > > On Mon, Dec 30, 2024 at 6:53=E2=80=AFPM Rik van Riel > > > > only those upper-level entries that lead to the target PTE in > > > > the page table hierarchy, leaving unrelated upper-level entries > > > > intact. > > > > > > How does this patch interact with KVM SVM guests? > > > In particular, will this patch cause TLB flushes performed by guest > > > kernels to behave differently? No. EFER is context switched by hardware on VMRUN and #VMEXIT, i.e. the gu= est runs with its own EFER, and thus will get the targeted flushes if and only = if the hypervisor virtualizes EFER.TCE *and* the guest explicitly enables EFER= .TCE. > > That is a good question. > > > > A Linux guest should be fine, since Linux already flushes the parts of = the > > TLB where page tables are being freed. > > > > I don't know whether this could potentially break some non-Linux guests= , > > though.