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charset=us-ascii Content-Disposition: inline In-Reply-To: <20250705071717.5062-7-ankita@nvidia.com> X-Stat-Signature: bqfdzdhij6b465ry7swtdm4z3t6aiu6h X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: AC577120006 X-HE-Tag: 1751850194-756499 X-HE-Meta: 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 O7t2I4oI TPq5e4CJVJ+Mx22xWRDnl0Yo7NLQA1F2daby/MqYqgoHJOiCb4NCXJbUKP6g3Xw1lu2PLGeCjs+wKYA2N7vWwvsKJ/BpUotkuCrUG3xyqUpwDmHrXZqQj8TNIMl3kRBmu8zGWb38JinSBt++sBxWBxxL56MrChnImlw25PhZupyZtbHI+LpSD9oia/8BOLQ26E64OCEqXPd1SpOzOi3fyedg3rkn84xAC2x6f1NpblwpmgL5GYvccTpWUao9x1LwduqBKxsoSDyJAJV4NW0uVY94aon7dZdRcMEzbrcRLFty78ZEtNaMnLseDT5WuwWB6ibzuxKYhF7aEWRi3WS93fdi0MMD0h7Sh+u//RlvZtcVZPMfJj2sGjo7Zi2qDUI4O1yoGzEPGsZZ90bFuK2BK91o9wW600C4t7/sq6b7F7zze2Vr3JSLrXFYV728yPfLUuC+tf1e5Zbqe9ZvGjLqHFKlY2BetgUeLRjJi 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 Sat, Jul 05, 2025 at 07:17:17AM +0000, ankita@nvidia.com wrote: > From: Ankit Agrawal > > Introduce a new KVM capability to expose to the userspace whether > cacheable mapping of PFNMAP is supported. > > The ability to safely do the cacheable mapping of PFNMAP is contingent > on S2FWB and ARM64_HAS_CACHE_DIC. S2FWB allows KVM to avoid flushing > the D cache, ARM64_HAS_CACHE_DIC allows KVM to avoid flushing the icache > and turns icache_inval_pou() into a NOP. The cap would be false if > those requirements are missing and is checked by making use of > kvm_arch_supports_cacheable_pfnmap. > > This capability would allow userspace to discover the support. > It could for instance be used by userspace to prevent live-migration > across FWB and non-FWB hosts. > > CC: Catalin Marinas > CC: Jason Gunthorpe > CC: Oliver Upton > CC: David Hildenbrand > Suggested-by: Marc Zyngier > Reviewed-by: Jason Gunthorpe > Tested-by: Donald Dutile > Signed-off-by: Ankit Agrawal Reviewed-by: Catalin Marinas