[syserror] Split usermem package

Split usermem package to help remove syserror dependency in go_marshal.
New hostarch package contains code not dependent on syserror.

PiperOrigin-RevId: 365651233

13 files changed, 81 insertions, 81 deletions

diff --git a/pkg/sentry/platform/kvm/BUILD b/pkg/sentry/platform/kvm/BUILD
index 03a76eb9b..f04898dc1 100644
--- a/pkg/sentry/platform/kvm/BUILD
+++ b/pkg/sentry/platform/kvm/BUILD
@@ -43,6 +43,7 @@ go_library(
         "//pkg/atomicbitops",
         "//pkg/context",
         "//pkg/cpuid",
+        "//pkg/hostarch",
         "//pkg/log",
         "//pkg/procid",
         "//pkg/ring0",
@@ -56,7 +57,6 @@ go_library(
         "//pkg/sentry/platform/interrupt",
         "//pkg/sentry/time",
         "//pkg/sync",
-        "//pkg/usermem",
         "@org_golang_x_sys//unix:go_default_library",
     ],
 )
@@ -76,6 +76,7 @@ go_test(
         "requires-kvm",
     ],
     deps = [
+        "//pkg/hostarch",
         "//pkg/ring0",
         "//pkg/ring0/pagetables",
         "//pkg/sentry/arch",
@@ -83,7 +84,6 @@ go_test(
         "//pkg/sentry/platform",
         "//pkg/sentry/platform/kvm/testutil",
         "//pkg/sentry/time",
-        "//pkg/usermem",
         "@org_golang_x_sys//unix:go_default_library",
     ],
 )
diff --git a/pkg/sentry/platform/kvm/address_space.go b/pkg/sentry/platform/kvm/address_space.go
index 25c21e843..5524e8727 100644
--- a/pkg/sentry/platform/kvm/address_space.go
+++ b/pkg/sentry/platform/kvm/address_space.go
@@ -18,11 +18,11 @@ import (
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/atomicbitops"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/ring0/pagetables"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sync"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // dirtySet tracks vCPUs for invalidation.
@@ -118,7 +118,7 @@ type hostMapEntry struct {
 // +checkescape:hard,stack
 //
 //go:nosplit
-func (as *addressSpace) mapLocked(addr usermem.Addr, m hostMapEntry, at usermem.AccessType) (inv bool) {
+func (as *addressSpace) mapLocked(addr hostarch.Addr, m hostMapEntry, at hostarch.AccessType) (inv bool) {
 	for m.length > 0 {
 		physical, length, ok := translateToPhysical(m.addr)
 		if !ok {
@@ -144,14 +144,14 @@ func (as *addressSpace) mapLocked(addr usermem.Addr, m hostMapEntry, at usermem.
 		}, physical) || inv
 		m.addr += length
 		m.length -= length
-		addr += usermem.Addr(length)
+		addr += hostarch.Addr(length)
 	}
 
 	return inv
 }
 
 // MapFile implements platform.AddressSpace.MapFile.
-func (as *addressSpace) MapFile(addr usermem.Addr, f memmap.File, fr memmap.FileRange, at usermem.AccessType, precommit bool) error {
+func (as *addressSpace) MapFile(addr hostarch.Addr, f memmap.File, fr memmap.FileRange, at hostarch.AccessType, precommit bool) error {
 	as.mu.Lock()
 	defer as.mu.Unlock()
 
@@ -165,7 +165,7 @@ func (as *addressSpace) MapFile(addr usermem.Addr, f memmap.File, fr memmap.File
 	// We don't execute from application file-mapped memory, and guest page
 	// tables don't care if we have execute permission (but they do need pages
 	// to be readable).
-	bs, err := f.MapInternal(fr, usermem.AccessType{
+	bs, err := f.MapInternal(fr, hostarch.AccessType{
 		Read:  at.Read || at.Execute || precommit,
 		Write: at.Write,
 	})
@@ -187,7 +187,7 @@ func (as *addressSpace) MapFile(addr usermem.Addr, f memmap.File, fr memmap.File
 		// lookup in our host page tables for this translation.
 		if precommit {
 			s := b.ToSlice()
-			for i := 0; i < len(s); i += usermem.PageSize {
+			for i := 0; i < len(s); i += hostarch.PageSize {
 				_ = s[i] // Touch to commit.
 			}
 		}
@@ -201,7 +201,7 @@ func (as *addressSpace) MapFile(addr usermem.Addr, f memmap.File, fr memmap.File
 			length: uintptr(b.Len()),
 		}, at)
 		inv = inv || prev
-		addr += usermem.Addr(b.Len())
+		addr += hostarch.Addr(b.Len())
 	}
 	if inv {
 		as.invalidate()
@@ -215,12 +215,12 @@ func (as *addressSpace) MapFile(addr usermem.Addr, f memmap.File, fr memmap.File
 // +checkescape:hard,stack
 //
 //go:nosplit
-func (as *addressSpace) unmapLocked(addr usermem.Addr, length uint64) bool {
+func (as *addressSpace) unmapLocked(addr hostarch.Addr, length uint64) bool {
 	return as.pageTables.Unmap(addr, uintptr(length))
 }
 
 // Unmap unmaps the given range by calling pagetables.PageTables.Unmap.
-func (as *addressSpace) Unmap(addr usermem.Addr, length uint64) {
+func (as *addressSpace) Unmap(addr hostarch.Addr, length uint64) {
 	as.mu.Lock()
 	defer as.mu.Unlock()
 
diff --git a/pkg/sentry/platform/kvm/bluepill_fault.go b/pkg/sentry/platform/kvm/bluepill_fault.go
index 37c53fa02..28a613a54 100644
--- a/pkg/sentry/platform/kvm/bluepill_fault.go
+++ b/pkg/sentry/platform/kvm/bluepill_fault.go
@@ -18,7 +18,7 @@ import (
 	"sync/atomic"
 
 	"golang.org/x/sys/unix"
-	"gvisor.dev/gvisor/pkg/usermem"
+	"gvisor.dev/gvisor/pkg/hostarch"
 )
 
 const (
@@ -47,7 +47,7 @@ func yield() {
 //
 //go:nosplit
 func calculateBluepillFault(physical uintptr, phyRegions []physicalRegion) (virtualStart, physicalStart, length uintptr, ok bool) {
-	alignedPhysical := physical &^ uintptr(usermem.PageSize-1)
+	alignedPhysical := physical &^ uintptr(hostarch.PageSize-1)
 	for _, pr := range phyRegions {
 		end := pr.physical + pr.length
 		if physical < pr.physical || physical >= end {
diff --git a/pkg/sentry/platform/kvm/context.go b/pkg/sentry/platform/kvm/context.go
index 706fa53dc..f4d4473a8 100644
--- a/pkg/sentry/platform/kvm/context.go
+++ b/pkg/sentry/platform/kvm/context.go
@@ -18,11 +18,11 @@ import (
 	"sync/atomic"
 
 	pkgcontext "gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/ring0"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/interrupt"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // context is an implementation of the platform context.
@@ -40,7 +40,7 @@ type context struct {
 }
 
 // Switch runs the provided context in the given address space.
-func (c *context) Switch(ctx pkgcontext.Context, mm platform.MemoryManager, ac arch.Context, _ int32) (*arch.SignalInfo, usermem.AccessType, error) {
+func (c *context) Switch(ctx pkgcontext.Context, mm platform.MemoryManager, ac arch.Context, _ int32) (*arch.SignalInfo, hostarch.AccessType, error) {
 	as := mm.AddressSpace()
 	localAS := as.(*addressSpace)
 
@@ -50,7 +50,7 @@ func (c *context) Switch(ctx pkgcontext.Context, mm platform.MemoryManager, ac a
 	// Enable interrupts (i.e. calls to vCPU.Notify).
 	if !c.interrupt.Enable(cpu) {
 		c.machine.Put(cpu) // Already preempted.
-		return nil, usermem.NoAccess, platform.ErrContextInterrupt
+		return nil, hostarch.NoAccess, platform.ErrContextInterrupt
 	}
 
 	// Set the active address space.
diff --git a/pkg/sentry/platform/kvm/kvm.go b/pkg/sentry/platform/kvm/kvm.go
index 92c05a9ad..aac0fdffe 100644
--- a/pkg/sentry/platform/kvm/kvm.go
+++ b/pkg/sentry/platform/kvm/kvm.go
@@ -20,11 +20,11 @@ import (
 	"os"
 
 	"golang.org/x/sys/unix"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/ring0"
 	"gvisor.dev/gvisor/pkg/ring0/pagetables"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sync"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // userMemoryRegion is a region of physical memory.
@@ -146,13 +146,13 @@ func (*KVM) MapUnit() uint64 {
 }
 
 // MinUserAddress returns the lowest available address.
-func (*KVM) MinUserAddress() usermem.Addr {
-	return usermem.PageSize
+func (*KVM) MinUserAddress() hostarch.Addr {
+	return hostarch.PageSize
 }
 
 // MaxUserAddress returns the first address that may not be used.
-func (*KVM) MaxUserAddress() usermem.Addr {
-	return usermem.Addr(ring0.MaximumUserAddress)
+func (*KVM) MaxUserAddress() hostarch.Addr {
+	return hostarch.Addr(ring0.MaximumUserAddress)
 }
 
 // NewAddressSpace returns a new pagetable root.
diff --git a/pkg/sentry/platform/kvm/kvm_test.go b/pkg/sentry/platform/kvm/kvm_test.go
index 5bce16dde..ceff09a60 100644
--- a/pkg/sentry/platform/kvm/kvm_test.go
+++ b/pkg/sentry/platform/kvm/kvm_test.go
@@ -22,6 +22,7 @@ import (
 	"time"
 
 	"golang.org/x/sys/unix"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/ring0"
 	"gvisor.dev/gvisor/pkg/ring0/pagetables"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
@@ -29,7 +30,6 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/kvm/testutil"
 	ktime "gvisor.dev/gvisor/pkg/sentry/time"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 var dummyFPState = fpu.NewState()
@@ -142,8 +142,8 @@ func applicationTest(t testHarness, useHostMappings bool, target func(), fn func
 			// done for regular user code, but is fine for test
 			// purposes.)
 			applyPhysicalRegions(func(pr physicalRegion) bool {
-				pt.Map(usermem.Addr(pr.virtual), pr.length, pagetables.MapOpts{
-					AccessType: usermem.AnyAccess,
+				pt.Map(hostarch.Addr(pr.virtual), pr.length, pagetables.MapOpts{
+					AccessType: hostarch.AnyAccess,
 					User:       true,
 				}, pr.physical)
 				return true // Keep iterating.
@@ -351,7 +351,7 @@ func TestInvalidate(t *testing.T) {
 			break // Done.
 		}
 		// Unmap the page containing data & invalidate.
-		pt.Unmap(usermem.Addr(reflect.ValueOf(&data).Pointer() & ^uintptr(usermem.PageSize-1)), usermem.PageSize)
+		pt.Unmap(hostarch.Addr(reflect.ValueOf(&data).Pointer() & ^uintptr(hostarch.PageSize-1)), hostarch.PageSize)
 		for {
 			var si arch.SignalInfo
 			if _, err := c.SwitchToUser(ring0.SwitchOpts{
diff --git a/pkg/sentry/platform/kvm/machine.go b/pkg/sentry/platform/kvm/machine.go
index 5d586f257..b3d4188a3 100644
--- a/pkg/sentry/platform/kvm/machine.go
+++ b/pkg/sentry/platform/kvm/machine.go
@@ -21,13 +21,13 @@ import (
 
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/atomicbitops"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/procid"
 	"gvisor.dev/gvisor/pkg/ring0"
 	"gvisor.dev/gvisor/pkg/ring0/pagetables"
 	ktime "gvisor.dev/gvisor/pkg/sentry/time"
 	"gvisor.dev/gvisor/pkg/sync"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // machine contains state associated with the VM as a whole.
@@ -227,9 +227,9 @@ func newMachine(vm int) (*machine, error) {
 	applyPhysicalRegions(func(pr physicalRegion) bool {
 		// Map everything in the lower half.
 		m.kernel.PageTables.Map(
-			usermem.Addr(pr.virtual),
+			hostarch.Addr(pr.virtual),
 			pr.length,
-			pagetables.MapOpts{AccessType: usermem.AnyAccess},
+			pagetables.MapOpts{AccessType: hostarch.AnyAccess},
 			pr.physical)
 
 		return true // Keep iterating.
diff --git a/pkg/sentry/platform/kvm/machine_amd64.go b/pkg/sentry/platform/kvm/machine_amd64.go
index 3af96c7e5..e8e209249 100644
--- a/pkg/sentry/platform/kvm/machine_amd64.go
+++ b/pkg/sentry/platform/kvm/machine_amd64.go
@@ -24,13 +24,13 @@ import (
 
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/cpuid"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/ring0"
 	"gvisor.dev/gvisor/pkg/ring0/pagetables"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/arch/fpu"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	ktime "gvisor.dev/gvisor/pkg/sentry/time"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // initArchState initializes architecture-specific state.
@@ -41,7 +41,7 @@ func (m *machine) initArchState() error {
 		unix.SYS_IOCTL,
 		uintptr(m.fd),
 		_KVM_SET_TSS_ADDR,
-		uintptr(reservedMemory-(3*usermem.PageSize))); errno != 0 {
+		uintptr(reservedMemory-(3*hostarch.PageSize))); errno != 0 {
 		return errno
 	}
 
@@ -256,19 +256,19 @@ func (c *vCPU) setSystemTime() error {
 // nonCanonical generates a canonical address return.
 //
 //go:nosplit
-func nonCanonical(addr uint64, signal int32, info *arch.SignalInfo) (usermem.AccessType, error) {
+func nonCanonical(addr uint64, signal int32, info *arch.SignalInfo) (hostarch.AccessType, error) {
 	*info = arch.SignalInfo{
 		Signo: signal,
 		Code:  arch.SignalInfoKernel,
 	}
 	info.SetAddr(addr) // Include address.
-	return usermem.NoAccess, platform.ErrContextSignal
+	return hostarch.NoAccess, platform.ErrContextSignal
 }
 
 // fault generates an appropriate fault return.
 //
 //go:nosplit
-func (c *vCPU) fault(signal int32, info *arch.SignalInfo) (usermem.AccessType, error) {
+func (c *vCPU) fault(signal int32, info *arch.SignalInfo) (hostarch.AccessType, error) {
 	bluepill(c) // Probably no-op, but may not be.
 	faultAddr := ring0.ReadCR2()
 	code, user := c.ErrorCode()
@@ -276,12 +276,12 @@ func (c *vCPU) fault(signal int32, info *arch.SignalInfo) (usermem.AccessType, e
 		// The last fault serviced by this CPU was not a user
 		// fault, so we can't reliably trust the faultAddr or
 		// the code provided here. We need to re-execute.
-		return usermem.NoAccess, platform.ErrContextInterrupt
+		return hostarch.NoAccess, platform.ErrContextInterrupt
 	}
 	// Reset the pointed SignalInfo.
 	*info = arch.SignalInfo{Signo: signal}
 	info.SetAddr(uint64(faultAddr))
-	accessType := usermem.AccessType{
+	accessType := hostarch.AccessType{
 		Read:    code&(1<<1) == 0,
 		Write:   code&(1<<1) != 0,
 		Execute: code&(1<<4) != 0,
@@ -310,14 +310,14 @@ func loadByte(ptr *byte) byte {
 //go:nosplit
 func prefaultFloatingPointState(data *fpu.State) {
 	size := len(*data)
-	for i := 0; i < size; i += usermem.PageSize {
+	for i := 0; i < size; i += hostarch.PageSize {
 		loadByte(&(*data)[i])
 	}
 	loadByte(&(*data)[size-1])
 }
 
 // SwitchToUser unpacks architectural-details.
-func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo) (usermem.AccessType, error) {
+func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo) (hostarch.AccessType, error) {
 	// Check for canonical addresses.
 	if regs := switchOpts.Registers; !ring0.IsCanonical(regs.Rip) {
 		return nonCanonical(regs.Rip, int32(unix.SIGSEGV), info)
@@ -353,7 +353,7 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo)
 	switch vector {
 	case ring0.Syscall, ring0.SyscallInt80:
 		// Fast path: system call executed.
-		return usermem.NoAccess, nil
+		return hostarch.NoAccess, nil
 
 	case ring0.PageFault:
 		return c.fault(int32(unix.SIGSEGV), info)
@@ -364,7 +364,7 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo)
 			Code:  1, // TRAP_BRKPT (breakpoint).
 		}
 		info.SetAddr(switchOpts.Registers.Rip) // Include address.
-		return usermem.AccessType{}, platform.ErrContextSignal
+		return hostarch.AccessType{}, platform.ErrContextSignal
 
 	case ring0.GeneralProtectionFault,
 		ring0.SegmentNotPresent,
@@ -380,9 +380,9 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo)
 			// When CPUID faulting is enabled, we will generate a #GP(0) when
 			// userspace executes a CPUID instruction. This is handled above,
 			// because we need to be able to map and read user memory.
-			return usermem.AccessType{}, platform.ErrContextSignalCPUID
+			return hostarch.AccessType{}, platform.ErrContextSignalCPUID
 		}
-		return usermem.AccessType{}, platform.ErrContextSignal
+		return hostarch.AccessType{}, platform.ErrContextSignal
 
 	case ring0.InvalidOpcode:
 		*info = arch.SignalInfo{
@@ -390,7 +390,7 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo)
 			Code:  1, // ILL_ILLOPC (illegal opcode).
 		}
 		info.SetAddr(switchOpts.Registers.Rip) // Include address.
-		return usermem.AccessType{}, platform.ErrContextSignal
+		return hostarch.AccessType{}, platform.ErrContextSignal
 
 	case ring0.DivideByZero:
 		*info = arch.SignalInfo{
@@ -398,7 +398,7 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo)
 			Code:  1, // FPE_INTDIV (divide by zero).
 		}
 		info.SetAddr(switchOpts.Registers.Rip) // Include address.
-		return usermem.AccessType{}, platform.ErrContextSignal
+		return hostarch.AccessType{}, platform.ErrContextSignal
 
 	case ring0.Overflow:
 		*info = arch.SignalInfo{
@@ -406,7 +406,7 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo)
 			Code:  2, // FPE_INTOVF (integer overflow).
 		}
 		info.SetAddr(switchOpts.Registers.Rip) // Include address.
-		return usermem.AccessType{}, platform.ErrContextSignal
+		return hostarch.AccessType{}, platform.ErrContextSignal
 
 	case ring0.X87FloatingPointException,
 		ring0.SIMDFloatingPointException:
@@ -415,17 +415,17 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo)
 			Code:  7, // FPE_FLTINV (invalid operation).
 		}
 		info.SetAddr(switchOpts.Registers.Rip) // Include address.
-		return usermem.AccessType{}, platform.ErrContextSignal
+		return hostarch.AccessType{}, platform.ErrContextSignal
 
 	case ring0.Vector(bounce): // ring0.VirtualizationException
-		return usermem.NoAccess, platform.ErrContextInterrupt
+		return hostarch.NoAccess, platform.ErrContextInterrupt
 
 	case ring0.AlignmentCheck:
 		*info = arch.SignalInfo{
 			Signo: int32(unix.SIGBUS),
 			Code:  2, // BUS_ADRERR (physical address does not exist).
 		}
-		return usermem.NoAccess, platform.ErrContextSignal
+		return hostarch.NoAccess, platform.ErrContextSignal
 
 	case ring0.NMI:
 		// An NMI is generated only when a fault is not servicable by
@@ -471,9 +471,9 @@ func (m *machine) mapUpperHalf(pageTable *pagetables.PageTables) {
 				panic("impossible translation")
 			}
 			pageTable.Map(
-				usermem.Addr(ring0.KernelStartAddress|r.virtual),
+				hostarch.Addr(ring0.KernelStartAddress|r.virtual),
 				r.length,
-				pagetables.MapOpts{AccessType: usermem.Execute},
+				pagetables.MapOpts{AccessType: hostarch.Execute},
 				physical)
 		}
 	})
@@ -484,9 +484,9 @@ func (m *machine) mapUpperHalf(pageTable *pagetables.PageTables) {
 			panic("impossible translation")
 		}
 		pageTable.Map(
-			usermem.Addr(ring0.KernelStartAddress|start),
+			hostarch.Addr(ring0.KernelStartAddress|start),
 			regionLen,
-			pagetables.MapOpts{AccessType: usermem.ReadWrite},
+			pagetables.MapOpts{AccessType: hostarch.ReadWrite},
 			physical)
 	}
 }
diff --git a/pkg/sentry/platform/kvm/machine_arm64.go b/pkg/sentry/platform/kvm/machine_arm64.go
index 2edc9d1b2..03e84d804 100644
--- a/pkg/sentry/platform/kvm/machine_arm64.go
+++ b/pkg/sentry/platform/kvm/machine_arm64.go
@@ -17,12 +17,12 @@
 package kvm
 
 import (
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/ring0"
 	"gvisor.dev/gvisor/pkg/ring0/pagetables"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/arch/fpu"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 type vCPUArchState struct {
@@ -53,9 +53,9 @@ const (
 func (m *machine) mapUpperHalf(pageTable *pagetables.PageTables) {
 	applyPhysicalRegions(func(pr physicalRegion) bool {
 		pageTable.Map(
-			usermem.Addr(ring0.KernelStartAddress|pr.virtual),
+			hostarch.Addr(ring0.KernelStartAddress|pr.virtual),
 			pr.length,
-			pagetables.MapOpts{AccessType: usermem.AnyAccess, Global: true},
+			pagetables.MapOpts{AccessType: hostarch.AnyAccess, Global: true},
 			pr.physical)
 
 		return true // Keep iterating.
@@ -117,13 +117,13 @@ func availableRegionsForSetMem() (phyRegions []physicalRegion) {
 // nonCanonical generates a canonical address return.
 //
 //go:nosplit
-func nonCanonical(addr uint64, signal int32, info *arch.SignalInfo) (usermem.AccessType, error) {
+func nonCanonical(addr uint64, signal int32, info *arch.SignalInfo) (hostarch.AccessType, error) {
 	*info = arch.SignalInfo{
 		Signo: signal,
 		Code:  arch.SignalInfoKernel,
 	}
 	info.SetAddr(addr) // Include address.
-	return usermem.NoAccess, platform.ErrContextSignal
+	return hostarch.NoAccess, platform.ErrContextSignal
 }
 
 // isInstructionAbort returns true if it is an instruction abort.
@@ -148,7 +148,7 @@ func isWriteFault(code uint64) bool {
 // fault generates an appropriate fault return.
 //
 //go:nosplit
-func (c *vCPU) fault(signal int32, info *arch.SignalInfo) (usermem.AccessType, error) {
+func (c *vCPU) fault(signal int32, info *arch.SignalInfo) (hostarch.AccessType, error) {
 	bluepill(c) // Probably no-op, but may not be.
 	faultAddr := c.GetFaultAddr()
 	code, user := c.ErrorCode()
@@ -157,7 +157,7 @@ func (c *vCPU) fault(signal int32, info *arch.SignalInfo) (usermem.AccessType, e
 		// The last fault serviced by this CPU was not a user
 		// fault, so we can't reliably trust the faultAddr or
 		// the code provided here. We need to re-execute.
-		return usermem.NoAccess, platform.ErrContextInterrupt
+		return hostarch.NoAccess, platform.ErrContextInterrupt
 	}
 
 	// Reset the pointed SignalInfo.
@@ -174,7 +174,7 @@ func (c *vCPU) fault(signal int32, info *arch.SignalInfo) (usermem.AccessType, e
 		info.Code = 2
 	}
 
-	accessType := usermem.AccessType{
+	accessType := hostarch.AccessType{
 		Read:    !isWriteFault(uint64(code)),
 		Write:   isWriteFault(uint64(code)),
 		Execute: isInstructionAbort(uint64(code)),
diff --git a/pkg/sentry/platform/kvm/machine_arm64_unsafe.go b/pkg/sentry/platform/kvm/machine_arm64_unsafe.go
index e7d5f3193..634e55ec0 100644
--- a/pkg/sentry/platform/kvm/machine_arm64_unsafe.go
+++ b/pkg/sentry/platform/kvm/machine_arm64_unsafe.go
@@ -23,12 +23,12 @@ import (
 	"unsafe"
 
 	"golang.org/x/sys/unix"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/ring0"
 	"gvisor.dev/gvisor/pkg/ring0/pagetables"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/arch/fpu"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 type kvmVcpuInit struct {
@@ -209,7 +209,7 @@ func (c *vCPU) getOneRegister(reg *kvmOneReg) error {
 }
 
 // SwitchToUser unpacks architectural-details.
-func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo) (usermem.AccessType, error) {
+func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo) (hostarch.AccessType, error) {
 	// Check for canonical addresses.
 	if regs := switchOpts.Registers; !ring0.IsCanonical(regs.Pc) {
 		return nonCanonical(regs.Pc, int32(unix.SIGSEGV), info)
@@ -246,13 +246,13 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo)
 	switch vector {
 	case ring0.Syscall:
 		// Fast path: system call executed.
-		return usermem.NoAccess, nil
+		return hostarch.NoAccess, nil
 	case ring0.PageFault:
 		return c.fault(int32(unix.SIGSEGV), info)
 	case ring0.El0ErrNMI:
 		return c.fault(int32(unix.SIGBUS), info)
 	case ring0.Vector(bounce): // ring0.VirtualizationException.
-		return usermem.NoAccess, platform.ErrContextInterrupt
+		return hostarch.NoAccess, platform.ErrContextInterrupt
 	case ring0.El0SyncUndef:
 		return c.fault(int32(unix.SIGILL), info)
 	case ring0.El0SyncDbg:
@@ -261,16 +261,16 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo)
 			Code:  1, // TRAP_BRKPT (breakpoint).
 		}
 		info.SetAddr(switchOpts.Registers.Pc) // Include address.
-		return usermem.AccessType{}, platform.ErrContextSignal
+		return hostarch.AccessType{}, platform.ErrContextSignal
 	case ring0.El0SyncSpPc:
 		*info = arch.SignalInfo{
 			Signo: int32(unix.SIGBUS),
 			Code:  2, // BUS_ADRERR (physical address does not exist).
 		}
-		return usermem.NoAccess, platform.ErrContextSignal
+		return hostarch.NoAccess, platform.ErrContextSignal
 	case ring0.El0SyncSys,
 		ring0.El0SyncWfx:
-		return usermem.NoAccess, nil // skip for now.
+		return hostarch.NoAccess, nil // skip for now.
 	default:
 		panic(fmt.Sprintf("unexpected vector: 0x%x", vector))
 	}
diff --git a/pkg/sentry/platform/kvm/physical_map.go b/pkg/sentry/platform/kvm/physical_map.go
index 7376d8b8d..d812e6c26 100644
--- a/pkg/sentry/platform/kvm/physical_map.go
+++ b/pkg/sentry/platform/kvm/physical_map.go
@@ -19,9 +19,9 @@ import (
 	"sort"
 
 	"golang.org/x/sys/unix"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/ring0"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 type region struct {
@@ -81,7 +81,7 @@ func fillAddressSpace() (excludedRegions []region) {
 	// faultBlockSize, potentially causing up to faultBlockSize bytes in
 	// internal fragmentation for each physical region. So we need to
 	// account for this properly during allocation.
-	requiredAddr, ok := usermem.Addr(vSize - pSize + faultBlockSize).RoundUp()
+	requiredAddr, ok := hostarch.Addr(vSize - pSize + faultBlockSize).RoundUp()
 	if !ok {
 		panic(fmt.Sprintf(
 			"overflow for vSize (%x) - pSize (%x) + faultBlockSize (%x)",
@@ -99,7 +99,7 @@ func fillAddressSpace() (excludedRegions []region) {
 			0, 0)
 		if errno != 0 {
 			// Attempt half the size; overflow not possible.
-			currentAddr, _ := usermem.Addr(current >> 1).RoundUp()
+			currentAddr, _ := hostarch.Addr(current >> 1).RoundUp()
 			current = uintptr(currentAddr)
 			continue
 		}
@@ -134,8 +134,8 @@ func computePhysicalRegions(excludedRegions []region) (physicalRegions []physica
 			return
 		}
 		if virtual == 0 {
-			virtual += usermem.PageSize
-			length -= usermem.PageSize
+			virtual += hostarch.PageSize
+			length -= hostarch.PageSize
 		}
 		if end := virtual + length; end > ring0.MaximumUserAddress {
 			length -= (end - ring0.MaximumUserAddress)
diff --git a/pkg/sentry/platform/kvm/virtual_map.go b/pkg/sentry/platform/kvm/virtual_map.go
index 4dcdbf8a7..01d9eb39d 100644
--- a/pkg/sentry/platform/kvm/virtual_map.go
+++ b/pkg/sentry/platform/kvm/virtual_map.go
@@ -22,12 +22,12 @@ import (
 	"regexp"
 	"strconv"
 
-	"gvisor.dev/gvisor/pkg/usermem"
+	"gvisor.dev/gvisor/pkg/hostarch"
 )
 
 type virtualRegion struct {
 	region
-	accessType usermem.AccessType
+	accessType hostarch.AccessType
 	shared     bool
 	offset     uintptr
 	filename   string
@@ -92,7 +92,7 @@ func applyVirtualRegions(fn func(vr virtualRegion)) error {
 					virtual: uintptr(start),
 					length:  uintptr(end - start),
 				},
-				accessType: usermem.AccessType{
+				accessType: hostarch.AccessType{
 					Read:    read,
 					Write:   write,
 					Execute: execute,
diff --git a/pkg/sentry/platform/kvm/virtual_map_test.go b/pkg/sentry/platform/kvm/virtual_map_test.go
index 9b4545fdd..1f4a774f3 100644
--- a/pkg/sentry/platform/kvm/virtual_map_test.go
+++ b/pkg/sentry/platform/kvm/virtual_map_test.go
@@ -18,12 +18,12 @@ import (
 	"testing"
 
 	"golang.org/x/sys/unix"
-	"gvisor.dev/gvisor/pkg/usermem"
+	"gvisor.dev/gvisor/pkg/hostarch"
 )
 
 type checker struct {
 	ok         bool
-	accessType usermem.AccessType
+	accessType hostarch.AccessType
 }
 
 func (c *checker) Containing(addr uintptr) func(virtualRegion) {
@@ -46,7 +46,7 @@ func TestParseMaps(t *testing.T) {
 
 	// MMap a new page.
 	addr, _, errno := unix.RawSyscall6(
-		unix.SYS_MMAP, 0, usermem.PageSize,
+		unix.SYS_MMAP, 0, hostarch.PageSize,
 		unix.PROT_READ|unix.PROT_WRITE,
 		unix.MAP_ANONYMOUS|unix.MAP_PRIVATE, 0, 0)
 	if errno != 0 {
@@ -55,19 +55,19 @@ func TestParseMaps(t *testing.T) {
 
 	// Re-parse maps.
 	if err := applyVirtualRegions(c.Containing(addr)); err != nil {
-		unix.RawSyscall(unix.SYS_MUNMAP, addr, usermem.PageSize, 0)
+		unix.RawSyscall(unix.SYS_MUNMAP, addr, hostarch.PageSize, 0)
 		t.Fatalf("unexpected error: %v", err)
 	}
 
 	// Assert that it now does contain the region.
 	if !c.ok {
-		unix.RawSyscall(unix.SYS_MUNMAP, addr, usermem.PageSize, 0)
+		unix.RawSyscall(unix.SYS_MUNMAP, addr, hostarch.PageSize, 0)
 		t.Fatalf("updated map does not contain 0x%08x, expected true", addr)
 	}
 
 	// Map the region as PROT_NONE.
 	newAddr, _, errno := unix.RawSyscall6(
-		unix.SYS_MMAP, addr, usermem.PageSize,
+		unix.SYS_MMAP, addr, hostarch.PageSize,
 		unix.PROT_NONE,
 		unix.MAP_ANONYMOUS|unix.MAP_FIXED|unix.MAP_PRIVATE, 0, 0)
 	if errno != 0 {
@@ -89,5 +89,5 @@ func TestParseMaps(t *testing.T) {
 	}
 
 	// Unmap the region.
-	unix.RawSyscall(unix.SYS_MUNMAP, addr, usermem.PageSize, 0)
+	unix.RawSyscall(unix.SYS_MUNMAP, addr, hostarch.PageSize, 0)
 }