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Wed, 7 Sep 2022 09:41:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=stgolabs.net; s=dreamhost; t=1662568903; bh=2wCa/Jt/3D2I+rbeGjg1PPoBnNjJ68RfVRRwxhzeg9s=; h=Date:From:To:Cc:Subject:Content-Type; b=CxmwPOEIHGF6GhHFwaqiAV0i/CGO0vUy9SrwWioqRLNWsu7UDqUkf/t05zvlw4WId uzHh2WlTA6BLxr5RPUGj6m8BaW58oYsLTnhqe33Ik4Yx2AOvcSIMSY2lMGRTO3yR2e rp5uQcTQhhZc+VXsyx09X2vM2DTxLJd5aC9X5AiU/LaDs4qKtZMCcnERhFVo/20upA D2l5NQEfGVvd/SXUiDTyO5Bzkg+3/QGT/vEDYkAj5vwR3KlCiy+zQBJtASYndOEzkK OFNygZOz+42lYsGEg/VIifEr+LWZ0z3xm31lU5NgSa9Lc3/JIVLZ33bLwpaS9DATj6 qYpGmT8WRwpKw== Date: Wed, 7 Sep 2022 09:22:45 -0700 From: Davidlohr Bueso To: Borislav Petkov Cc: dan.j.williams@intel.com, x86@kernel.org, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, peterz@infradead.org, akpm@linux-foundation.org, dave.jiang@intel.com, Jonathan.Cameron@huawei.com, vishal.l.verma@intel.com, ira.weiny@intel.com, a.manzanares@samsung.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH -next] memregion: Add arch_flush_memregion() interface Message-ID: <20220907162245.5ddexpmibjbanrho@offworld> References: <20220829212918.4039240-1-dave@stgolabs.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20220429 Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org On Wed, 07 Sep 2022, Borislav Petkov wrote: >On Mon, Aug 29, 2022 at 02:29:18PM -0700, Davidlohr Bueso wrote: >> diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c >> index 1abd5438f126..18463cb704fb 100644 >> --- a/arch/x86/mm/pat/set_memory.c >> +++ b/arch/x86/mm/pat/set_memory.c >> @@ -330,6 +330,20 @@ void arch_invalidate_pmem(void *addr, size_t size) >> EXPORT_SYMBOL_GPL(arch_invalidate_pmem); >> #endif >> >> +#ifdef CONFIG_ARCH_HAS_MEMREGION_INVALIDATE >> +bool arch_has_flush_memregion(void) >> +{ >> + return !cpu_feature_enabled(X86_FEATURE_HYPERVISOR); > >This looks really weird. Why does this need to care about HV at all? So the context here is: e2efb6359e62 ("ACPICA: Avoid cache flush inside virtual machines") > >Does that nfit stuff even run in guests? No, nor does cxl. This was mostly in general a precautionary check such that the api is unavailable in VMs. > >> +EXPORT_SYMBOL(arch_has_flush_memregion); > >... > >> +EXPORT_SYMBOL(arch_flush_memregion); > >Why aren't those exports _GPL? Fine by me. Thanks, Davidlohr