On Thu, Mar 24, 2022 at 11:52:38AM -0400, Tamas K Lengyel wrote: > On Thu, Mar 24, 2022 at 11:46 AM Roger Pau Monné <[email protected]> wrote: > > > > On Tue, Mar 22, 2022 at 01:41:39PM -0400, Tamas K Lengyel wrote: > > > diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h > > > index 208d8dcbd9..30ce23c5a7 100644 > > > --- a/xen/include/public/memory.h > > > +++ b/xen/include/public/memory.h > > > @@ -541,12 +541,14 @@ struct xen_mem_sharing_op { > > > uint32_t gref; /* IN: gref to debug */ > > > } u; > > > } debug; > > > - struct mem_sharing_op_fork { /* OP_FORK */ > > > + struct mem_sharing_op_fork { /* OP_FORK/_RESET */ > > > domid_t parent_domain; /* IN: parent's domain id */ > > > /* These flags only makes sense for short-lived forks */ > > > #define XENMEM_FORK_WITH_IOMMU_ALLOWED (1u << 0) > > > #define XENMEM_FORK_BLOCK_INTERRUPTS (1u << 1) > > > #define XENMEM_FORK_SKIP_SPECIAL_PAGES (1u << 2) > > > +#define XENMEM_FORK_RESET_STATE (1u << 3) > > > +#define XENMEM_FORK_RESET_MEMORY (1u << 4) > > > uint16_t flags; /* IN: optional settings */ > > > uint32_t pad; /* Must be set to 0 */ > > > } fork; > > > diff --git a/xen/include/public/vm_event.h b/xen/include/public/vm_event.h > > > index bb003d21d0..81c2ee28cc 100644 > > > --- a/xen/include/public/vm_event.h > > > +++ b/xen/include/public/vm_event.h > > > @@ -127,6 +127,14 @@ > > > * Reset the vmtrace buffer (if vmtrace is enabled) > > > */ > > > #define VM_EVENT_FLAG_RESET_VMTRACE (1 << 13) > > > +/* > > > + * Reset the VM state (if VM is fork) > > > + */ > > > +#define VM_EVENT_FLAG_RESET_FORK_STATE (1 << 14) > > > +/* > > > + * Remove unshared entried from physmap (if VM is fork) > > > + */ > > > +#define VM_EVENT_FLAG_RESET_FORK_MEMORY (1 << 15) > > > > I'm confused about why two different interfaces are added to do this > > kind of selective resets, one to vm_event and one to xenmem_fork? > > > > I thin k the natural place for the option to live would be > > XENMEM_FORK? > > Yes, that's the natural place for it. But we are adding it to both for > a reason. In our use-case the reset operation will happen after a > vm_event is received to which we already must send a reply. Setting > the flag on the vm_event reply saves us having to issue an extra memop > hypercall afterwards.
Can you do a multicall and batch both operations in a single hypercall? That would seem more natural than adding duplicated interfaces. Thanks, Roger.
