honeycrisp/unimem/experiments/dext_contiguous_alloc/dext/CybMemAllocDriver.iig

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//
// CybMemAllocDriver.iig
//
// DriverKit interface definition for contiguous physical memory allocator.
//
// This DEXT allocates physically contiguous memory via IOBufferMemoryDescriptor
// and exposes it to userspace clients through ExternalMethod and memory mapping.
//

#ifndef CybMemAllocDriver_h
#define CybMemAllocDriver_h

#include <Availability.h>
#include <DriverKit/IOService.iig>
#include <DriverKit/IOUserClient.iig>

// External method selectors
enum {
    kCybMemAllocGetInfo       = 0,  // Get allocation info (size, flags)
    kCybMemAllocGetSegments   = 1,  // Get physical segment list
    kCybMemAllocMethodCount   = 2,
};

// Memory type for clientMemoryForType
enum {
    kCybMemAllocMemoryType    = 0,  // The contiguous buffer
};

// โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€
// CybMemAllocDriver: IOUserClient subclass
//
// One instance per userspace connection. On Start(), allocates a
// physically contiguous IOBufferMemoryDescriptor. Exposes it via:
//   - ExternalMethod selector 0: returns allocation metadata
//   - ExternalMethod selector 1: returns physical segment addresses
//   - CopyClientMemoryForType: maps the buffer into client address space
// โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€

class CybMemAllocDriver : public IOUserClient
{
public:
    // IOService lifecycle
    virtual bool init() override;
    virtual kern_return_t Start(IOService * provider) override;
    virtual kern_return_t Stop(IOService * provider) override;
    virtual void free() override;

    // IOUserClient: external method dispatch
    virtual kern_return_t ExternalMethod(
        uint64_t             selector,
        IOUserClientMethodArguments * arguments,
        const IOUserClientMethodDispatch * dispatch,
        OSObject           * target,
        void               * reference) override;

    // IOUserClient: memory mapping for client
    virtual kern_return_t CopyClientMemoryForType(
        uint64_t             type,
        uint64_t           * options,
        IOMemoryDescriptor ** memory) override;
};

#endif /* CybMemAllocDriver_h */

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