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-rw-r--r--pkg/sentry/platform/kvm/bluepill_amd64_unsafe.go7
-rw-r--r--pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go13
-rw-r--r--pkg/sentry/platform/kvm/bluepill_unsafe.go39
-rw-r--r--pkg/sentry/platform/kvm/kvm_arm64.go3
-rw-r--r--pkg/sentry/platform/kvm/kvm_const.go10
-rw-r--r--pkg/sentry/platform/kvm/kvm_const_arm64.go7
-rw-r--r--pkg/sentry/platform/kvm/machine_arm64_unsafe.go4
-rw-r--r--pkg/sentry/platform/ring0/entry_arm64.s14
8 files changed, 81 insertions, 16 deletions
diff --git a/pkg/sentry/platform/kvm/bluepill_amd64_unsafe.go b/pkg/sentry/platform/kvm/bluepill_amd64_unsafe.go
index 99cac665d..0d1e83e6c 100644
--- a/pkg/sentry/platform/kvm/bluepill_amd64_unsafe.go
+++ b/pkg/sentry/platform/kvm/bluepill_amd64_unsafe.go
@@ -53,3 +53,10 @@ func dieArchSetup(c *vCPU, context *arch.SignalContext64, guestRegs *userRegs) {
context.Rbx = uint64(uintptr(unsafe.Pointer(c)))
context.Rip = uint64(dieTrampolineAddr)
}
+
+// getHypercallID returns hypercall ID.
+//
+//go:nosplit
+func getHypercallID(addr uintptr) int {
+ return _KVM_HYPERCALL_MAX
+}
diff --git a/pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go b/pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go
index 4ca2b7717..abd36f973 100644
--- a/pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go
+++ b/pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go
@@ -61,3 +61,16 @@ func dieArchSetup(c *vCPU, context *arch.SignalContext64, guestRegs *userRegs) {
func bluepillArchFpContext(context unsafe.Pointer) *arch.FpsimdContext {
return &((*arch.SignalContext64)(context).Fpsimd64)
}
+
+// getHypercallID returns hypercall ID.
+//
+// On Arm64, the MMIO address should be 64-bit aligned.
+//
+//go:nosplit
+func getHypercallID(addr uintptr) int {
+ if addr < arm64HypercallMMIOBase || addr >= (arm64HypercallMMIOBase+_AARCH64_HYPERCALL_MMIO_SIZE) {
+ return _KVM_HYPERCALL_MAX
+ } else {
+ return int(((addr) - arm64HypercallMMIOBase) >> 3)
+ }
+}
diff --git a/pkg/sentry/platform/kvm/bluepill_unsafe.go b/pkg/sentry/platform/kvm/bluepill_unsafe.go
index 9add7c944..e79097b5d 100644
--- a/pkg/sentry/platform/kvm/bluepill_unsafe.go
+++ b/pkg/sentry/platform/kvm/bluepill_unsafe.go
@@ -58,6 +58,24 @@ func bluepillArchContext(context unsafe.Pointer) *arch.SignalContext64 {
return &((*arch.UContext64)(context).MContext)
}
+// bluepillHandleHlt is reponsible for handling VM-Exit.
+//
+//go:nosplit
+func bluepillGuestExit(c *vCPU, context unsafe.Pointer) {
+ // Copy out registers.
+ bluepillArchExit(c, bluepillArchContext(context))
+
+ // Return to the vCPUReady state; notify any waiters.
+ user := atomic.LoadUint32(&c.state) & vCPUUser
+ switch atomic.SwapUint32(&c.state, user) {
+ case user | vCPUGuest: // Expected case.
+ case user | vCPUGuest | vCPUWaiter:
+ c.notify()
+ default:
+ throw("invalid state")
+ }
+}
+
// bluepillHandler is called from the signal stub.
//
// The world may be stopped while this is executing, and it executes on the
@@ -156,25 +174,20 @@ func bluepillHandler(context unsafe.Pointer) {
c.die(bluepillArchContext(context), "debug")
return
case _KVM_EXIT_HLT:
- // Copy out registers.
- bluepillArchExit(c, bluepillArchContext(context))
-
- // Return to the vCPUReady state; notify any waiters.
- user := atomic.LoadUint32(&c.state) & vCPUUser
- switch atomic.SwapUint32(&c.state, user) {
- case user | vCPUGuest: // Expected case.
- case user | vCPUGuest | vCPUWaiter:
- c.notify()
- default:
- throw("invalid state")
- }
+ bluepillGuestExit(c, context)
return
case _KVM_EXIT_MMIO:
+ physical := uintptr(c.runData.data[0])
+ if getHypercallID(physical) == _KVM_HYPERCALL_VMEXIT {
+ bluepillGuestExit(c, context)
+ return
+ }
+
// Increment the fault count.
atomic.AddUint32(&c.faults, 1)
// For MMIO, the physical address is the first data item.
- physical := uintptr(c.runData.data[0])
+ physical = uintptr(c.runData.data[0])
virtual, ok := handleBluepillFault(c.machine, physical, physicalRegions, _KVM_MEM_FLAGS_NONE)
if !ok {
c.die(bluepillArchContext(context), "invalid physical address")
diff --git a/pkg/sentry/platform/kvm/kvm_arm64.go b/pkg/sentry/platform/kvm/kvm_arm64.go
index 29d457a7e..3134a076b 100644
--- a/pkg/sentry/platform/kvm/kvm_arm64.go
+++ b/pkg/sentry/platform/kvm/kvm_arm64.go
@@ -26,6 +26,9 @@ type kvmOneReg struct {
addr uint64
}
+// arm64HypercallMMIOBase is MMIO base address used to dispatch hypercalls.
+var arm64HypercallMMIOBase uintptr
+
const KVM_NR_SPSR = 5
type userFpsimdState struct {
diff --git a/pkg/sentry/platform/kvm/kvm_const.go b/pkg/sentry/platform/kvm/kvm_const.go
index 1d5c77ff4..6a7676468 100644
--- a/pkg/sentry/platform/kvm/kvm_const.go
+++ b/pkg/sentry/platform/kvm/kvm_const.go
@@ -71,3 +71,13 @@ const (
_KVM_MEM_READONLY = uint32(1) << 1
_KVM_MEM_FLAGS_NONE = 0
)
+
+// KVM hypercall list.
+// Canonical list of hypercalls supported.
+const (
+ // On amd64, it uses 'HLT' to leave the guest.
+ // Unlike amd64, arm64 can only uses mmio_exit/psci to leave the guest.
+ // _KVM_HYPERCALL_VMEXIT is only used on Arm64 for now.
+ _KVM_HYPERCALL_VMEXIT int = iota
+ _KVM_HYPERCALL_MAX
+)
diff --git a/pkg/sentry/platform/kvm/kvm_const_arm64.go b/pkg/sentry/platform/kvm/kvm_const_arm64.go
index 531ae8b1e..6f0539c29 100644
--- a/pkg/sentry/platform/kvm/kvm_const_arm64.go
+++ b/pkg/sentry/platform/kvm/kvm_const_arm64.go
@@ -131,3 +131,10 @@ const (
_ESR_SEGV_PEMERR_L2 = 0xe
_ESR_SEGV_PEMERR_L3 = 0xf
)
+
+// Arm64: MMIO base address used to dispatch hypercalls.
+const (
+ // on Arm64, the MMIO address must be 64-bit aligned.
+ // Currently, we only need 1 hypercall: hypercall_vmexit.
+ _AARCH64_HYPERCALL_MMIO_SIZE = 1 << 3
+)
diff --git a/pkg/sentry/platform/kvm/machine_arm64_unsafe.go b/pkg/sentry/platform/kvm/machine_arm64_unsafe.go
index 3c02cef7c..48c834499 100644
--- a/pkg/sentry/platform/kvm/machine_arm64_unsafe.go
+++ b/pkg/sentry/platform/kvm/machine_arm64_unsafe.go
@@ -159,6 +159,10 @@ func (c *vCPU) initArchState() error {
return err
}
+ // Use the address of the exception vector table as
+ // the MMIO address base.
+ arm64HypercallMMIOBase = toLocation
+
data = ring0.PsrDefaultSet | ring0.KernelFlagsSet
reg.id = _KVM_ARM64_REGS_PSTATE
if err := c.setOneRegister(&reg); err != nil {
diff --git a/pkg/sentry/platform/ring0/entry_arm64.s b/pkg/sentry/platform/ring0/entry_arm64.s
index db6465663..2bc5f3ecd 100644
--- a/pkg/sentry/platform/ring0/entry_arm64.s
+++ b/pkg/sentry/platform/ring0/entry_arm64.s
@@ -362,9 +362,17 @@ mmio_exit:
MOVD R1, CPU_LAZY_VFP(RSV_REG)
VFP_DISABLE
- // MMIO_EXIT.
- MOVD $0, R9
- MOVD R0, 0xffff000000001000(R9)
+ // Trigger MMIO_EXIT/_KVM_HYPERCALL_VMEXIT.
+ //
+ // To keep it simple, I used the address of exception table as the
+ // MMIO base address, so that I can trigger a MMIO-EXIT by forcibly writing
+ // a read-only space.
+ // Also, the length is engough to match a sufficient number of hypercall ID.
+ // Then, in host user space, I can calculate this address to find out
+ // which hypercall.
+ MRS VBAR_EL1, R9
+ MOVD R0, 0x0(R9)
+
RET
// HaltAndResume halts execution and point the pointer to the resume function.
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-26 17:38:00 +0000