add asid support to Arm64

 Support the operation of asid, so that I can optimize tlb performance
by combining with nG.

Signed-off-by: Bin Lu <bin.lu@arm.com>

2 files changed, 19 insertions, 1 deletions

diff --git a/pkg/sentry/platform/kvm/kvm_arm64_unsafe.go b/pkg/sentry/platform/kvm/kvm_arm64_unsafe.go
index 6531bae1d..48ccf8474 100644
--- a/pkg/sentry/platform/kvm/kvm_arm64_unsafe.go
+++ b/pkg/sentry/platform/kvm/kvm_arm64_unsafe.go
@@ -22,7 +22,8 @@ import (
 )
 
 var (
-	runDataSize int
+	runDataSize  int
+	hasGuestPCID bool
 )
 
 func updateSystemValues(fd int) error {
@@ -33,6 +34,7 @@ func updateSystemValues(fd int) error {
 	}
 	// Save the data.
 	runDataSize = int(sz)
+	hasGuestPCID = true
 
 	// Success.
 	return nil
diff --git a/pkg/sentry/platform/kvm/machine_arm64_unsafe.go b/pkg/sentry/platform/kvm/machine_arm64_unsafe.go
index 3de309c1a..ff8c068c0 100644
--- a/pkg/sentry/platform/kvm/machine_arm64_unsafe.go
+++ b/pkg/sentry/platform/kvm/machine_arm64_unsafe.go
@@ -26,6 +26,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0"
+	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
 	"gvisor.dev/gvisor/pkg/usermem"
 )
 
@@ -156,6 +157,14 @@ func (c *vCPU) initArchState() error {
 		return err
 	}
 
+	// Initialize the PCID database.
+	if hasGuestPCID {
+		// Note that NewPCIDs may return a nil table here, in which
+		// case we simply don't use PCID support (see below). In
+		// practice, this should not happen, however.
+		c.PCIDs = pagetables.NewPCIDs(fixedKernelPCID+1, poolPCIDs)
+	}
+
 	c.floatingPointState = arch.NewFloatingPointData()
 	return nil
 }
@@ -234,6 +243,13 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo)
 		return nonCanonical(regs.Sp, int32(syscall.SIGBUS), info)
 	}
 
+	// Assign PCIDs.
+	if c.PCIDs != nil {
+		var requireFlushPCID bool // Force a flush?
+		switchOpts.UserASID, requireFlushPCID = c.PCIDs.Assign(switchOpts.PageTables)
+		switchOpts.Flush = switchOpts.Flush || requireFlushPCID
+	}
+
 	var vector ring0.Vector
 	ttbr0App := switchOpts.PageTables.TTBR0_EL1(false, 0)
 	c.SetTtbr0App(uintptr(ttbr0App))