On 08.09.25 09:39, Kevin Brodsky wrote:
Commit 49147beb0ccb ("x86/xen: allow nesting of same lazy mode") originally introduced support for nested lazy sections (LAZY_MMU and LAZY_CPU). It later got reverted by commit c36549ff8d84 as its implementation turned out to be intolerant to preemption.Now that the lazy_mmu API allows enter() to pass through a state to the matching leave() call, we can support nesting again for the LAZY_MMU mode in a preemption-safe manner. If xen_enter_lazy_mmu() is called inside an active lazy_mmu section, xen_lazy_mode will already be set to XEN_LAZY_MMU and we can then return LAZY_MMU_NESTED to instruct the matching xen_leave_lazy_mmu() call to leave xen_lazy_mode unchanged. The only effect of this patch is to ensure that xen_lazy_mode remains set to XEN_LAZY_MMU until the outermost lazy_mmu section ends. xen_leave_lazy_mmu() still calls xen_mc_flush() unconditionally. Signed-off-by: Kevin Brodsky <[email protected]>
Reviewed-by: Juergen Gross <[email protected]> Juergen
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