1 files changed, 122 insertions, 0 deletions
diff --git a/pkg/sentry/platform/kvm/machine_arm64.go b/pkg/sentry/platform/kvm/machine_arm64.go
index b7e2cfb9d..7ae47f291 100755
--- a/pkg/sentry/platform/kvm/machine_arm64.go
+++ b/pkg/sentry/platform/kvm/machine_arm64.go
@@ -12,8 +12,38 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// +build arm64
+
 package kvm
 
+import (
+	"gvisor.dev/gvisor/pkg/sentry/arch"
+	"gvisor.dev/gvisor/pkg/sentry/platform"
+	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
+	"gvisor.dev/gvisor/pkg/sentry/usermem"
+)
+
+type vCPUArchState struct {
+	// PCIDs is the set of PCIDs for this vCPU.
+	//
+	// This starts above fixedKernelPCID.
+	PCIDs *pagetables.PCIDs
+}
+
+const (
+	// fixedKernelPCID is a fixed kernel PCID used for the kernel page
+	// tables. We must start allocating user PCIDs above this in order to
+	// avoid any conflict (see below).
+	fixedKernelPCID = 1
+
+	// poolPCIDs is the number of PCIDs to record in the database. As this
+	// grows, assignment can take longer, since it is a simple linear scan.
+	// Beyond a relatively small number, there are likely few perform
+	// benefits, since the TLB has likely long since lost any translations
+	// from more than a few PCIDs past.
+	poolPCIDs = 8
+)
+
 // Get all read-only physicalRegions.
 func rdonlyRegionsForSetMem() (phyRegions []physicalRegion) {
 	var rdonlyRegions []region
@@ -59,3 +89,95 @@ func availableRegionsForSetMem() (phyRegions []physicalRegion) {
 
 	return phyRegions
 }
+
+// dropPageTables drops cached page table entries.
+func (m *machine) dropPageTables(pt *pagetables.PageTables) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	// Clear from all PCIDs.
+	for _, c := range m.vCPUs {
+		c.PCIDs.Drop(pt)
+	}
+}
+
+// nonCanonical generates a canonical address return.
+//
+//go:nosplit
+func nonCanonical(addr uint64, signal int32, info *arch.SignalInfo) (usermem.AccessType, error) {
+	*info = arch.SignalInfo{
+		Signo: signal,
+		Code:  arch.SignalInfoKernel,
+	}
+	info.SetAddr(addr) // Include address.
+	return usermem.NoAccess, platform.ErrContextSignal
+}
+
+// fault generates an appropriate fault return.
+//
+//go:nosplit
+func (c *vCPU) fault(signal int32, info *arch.SignalInfo) (usermem.AccessType, error) {
+	faultAddr := c.GetFaultAddr()
+	code, user := c.ErrorCode()
+
+	// Reset the pointed SignalInfo.
+	*info = arch.SignalInfo{Signo: signal}
+	info.SetAddr(uint64(faultAddr))
+
+	read := true
+	write := false
+	execute := true
+
+	ret := code & _ESR_ELx_FSC
+	switch ret {
+	case _ESR_SEGV_MAPERR_L0, _ESR_SEGV_MAPERR_L1, _ESR_SEGV_MAPERR_L2, _ESR_SEGV_MAPERR_L3:
+		info.Code = 1 //SEGV_MAPERR
+		read = false
+		write = true
+		execute = false
+	case _ESR_SEGV_ACCERR_L1, _ESR_SEGV_ACCERR_L2, _ESR_SEGV_ACCERR_L3, _ESR_SEGV_PEMERR_L1, _ESR_SEGV_PEMERR_L2, _ESR_SEGV_PEMERR_L3:
+		info.Code = 2 // SEGV_ACCERR.
+		read = true
+		write = false
+		execute = false
+	default:
+		info.Code = 2
+	}
+
+	if !user {
+		read = true
+		write = false
+		execute = true
+
+	}
+	accessType := usermem.AccessType{
+		Read:    read,
+		Write:   write,
+		Execute: execute,
+	}
+
+	return accessType, platform.ErrContextSignal
+}
+
+// retryInGuest runs the given function in guest mode.
+//
+// If the function does not complete in guest mode (due to execution of a
+// system call due to a GC stall, for example), then it will be retried. The
+// given function must be idempotent as a result of the retry mechanism.
+func (m *machine) retryInGuest(fn func()) {
+	c := m.Get()
+	defer m.Put(c)
+	for {
+		c.ClearErrorCode() // See below.
+		bluepill(c)        // Force guest mode.
+		fn()               // Execute the given function.
+		_, user := c.ErrorCode()
+		if user {
+			// If user is set, then we haven't bailed back to host
+			// mode via a kernel exception or system call. We
+			// consider the full function to have executed in guest
+			// mode and we can return.
+			break
+		}
+	}
+}