On Mon, Feb 10, 2025 at 07:52:18PM +0000, Mark Rutland wrote: > These patches fix some issues with the way KVM manages FPSIMD/SVE/SME > state. The series supersedes my earlier attempt at fixing the host SVE > state corruption issue: > > https://lore.kernel.org/linux-arm-kernel/20250121100026.3974971-1-mark.rutland@xxxxxxx/ > > Patch 1 addresses the host SVE state corruption issue by always saving > and unbinding the host state when loading a vCPU, as discussed on the > earlier patch: > > https://lore.kernel.org/linux-arm-kernel/Z4--YuG5SWrP_pW7@J2N7QTR9R3/ > https://lore.kernel.org/linux-arm-kernel/86plkful48.wl-maz@xxxxxxxxxx/ > > Patches 2 to 4 remove code made redundant by patch 1. These probably > warrant backporting along with patch 1 as there is some historical > brokenness in the code they remove. > > Patches 5 to 7 are preparatory refactoring for patch 8, and are not > intended to have any functional impact. > > Patch 8 addresses some mismanagement of ZCR_EL{1,2} which can result in > the host VMM unexpectedly receiving a SIGKILL. To fix this, we eagerly > switch ZCR_EL{1,2} at guest<->host transitions, as discussed on another > series: > > https://lore.kernel.org/linux-arm-kernel/Z4pAMaEYvdLpmbg2@J2N7QTR9R3/ > https://lore.kernel.org/linux-arm-kernel/86o6zzukwr.wl-maz@xxxxxxxxxx/ > https://lore.kernel.org/linux-arm-kernel/Z5Dc-WMu2azhTuMn@J2N7QTR9R3/ > > The end result is that KVM loses ~100 lines of code, and becomes a bit > simpler to reason about. LGTM, although a minor nitpick would be to repack the host data flags at the end of purging SVE/SME. Reviewed-by: Oliver Upton <oliver.upton@xxxxxxxxx> -- Thanks, Oliver
