> -----Original Message----- > From: Eric Auger <[email protected]> > Sent: 02 October 2025 11:05 > To: Shameer Kolothum <[email protected]>; qemu- > [email protected]; [email protected] > Cc: [email protected]; Jason Gunthorpe <[email protected]>; Nicolin > Chen <[email protected]>; [email protected]; [email protected]; > Nathan Chen <[email protected]>; Matt Ochs <[email protected]>; > [email protected]; [email protected]; > [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected] > Subject: Re: [PATCH v4 09/27] hw/arm/smmuv3-accel: Support nested STE > install/uninstall support > > External email: Use caution opening links or attachments > > > Hi Shameer, > > On 9/29/25 3:36 PM, Shameer Kolothum wrote: > > From: Nicolin Chen <[email protected]> > > > > Allocates a s1 HWPT for the Guest s1 stage and attaches that to the > > pass-through vfio device. This will be invoked when Guest issues > > SMMU_CMD_CFGI_STE/STE_RANGE. > ON set both alloc + attachment are done. On unset you shall explain the > gym related to config/abort hwpt. Those are S1 hwpt, right? I think this > shall be reflected in the name to make it clearer? In the previous patch > I didn't really understand that.
Ok. There are three HWPTs in play here. BYPASS HWPT ABORT HWPT S1 HWPT --> This is when Guest has a valid S1 (STE_VALID && STE_CFG_S1_ENABLED) In previous patch we allocate a common BYPASS and ABORT HWPT for all devices in a vIOMMU. We reuse that here in this patch and attach if Guest request a S1 bypass or abort case. The S1 HWPT is allocated as and when the Guest has a valid STE with context descriptor and use that for attachment. Whether we can call them S1 HWPT only, I am not sure. Because, I think, during alloc() call the kernel allocates a Nested HWPT(IOMMU_DOMAIN_NESTED) which uses a Guest S1 nested on a S2 HWPT. Anyway, I will rephrase the comments and variable names to make it clear. Thanks, Shameer
