github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/sentry/platform/kvm/kvm_amd64_test.go (about)

     1  // Copyright 2020 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // +build amd64
    16  
    17  package kvm
    18  
    19  import (
    20  	"testing"
    21  
    22  	"github.com/SagerNet/gvisor/pkg/abi/linux"
    23  	"github.com/SagerNet/gvisor/pkg/ring0"
    24  	"github.com/SagerNet/gvisor/pkg/ring0/pagetables"
    25  	"github.com/SagerNet/gvisor/pkg/sentry/arch"
    26  	"github.com/SagerNet/gvisor/pkg/sentry/platform"
    27  	"github.com/SagerNet/gvisor/pkg/sentry/platform/kvm/testutil"
    28  )
    29  
    30  func TestSegments(t *testing.T) {
    31  	applicationTest(t, true, testutil.TwiddleSegments, func(c *vCPU, regs *arch.Registers, pt *pagetables.PageTables) bool {
    32  		testutil.SetTestSegments(regs)
    33  		for {
    34  			var si linux.SignalInfo
    35  			if _, err := c.SwitchToUser(ring0.SwitchOpts{
    36  				Registers:          regs,
    37  				FloatingPointState: &dummyFPState,
    38  				PageTables:         pt,
    39  				FullRestore:        true,
    40  			}, &si); err == platform.ErrContextInterrupt {
    41  				continue // Retry.
    42  			} else if err != nil {
    43  				t.Errorf("application segment check with full restore got unexpected error: %v", err)
    44  			}
    45  			if err := testutil.CheckTestSegments(regs); err != nil {
    46  				t.Errorf("application segment check with full restore failed: %v", err)
    47  			}
    48  			break // Done.
    49  		}
    50  		return false
    51  	})
    52  }
    53  
    54  // stmxcsr reads the MXCSR control and status register.
    55  func stmxcsr(addr *uint32)
    56  
    57  func TestMXCSR(t *testing.T) {
    58  	applicationTest(t, true, testutil.SyscallLoop, func(c *vCPU, regs *arch.Registers, pt *pagetables.PageTables) bool {
    59  		var si linux.SignalInfo
    60  		switchOpts := ring0.SwitchOpts{
    61  			Registers:          regs,
    62  			FloatingPointState: &dummyFPState,
    63  			PageTables:         pt,
    64  			FullRestore:        true,
    65  		}
    66  
    67  		const mxcsrControllMask = uint32(0x1f80)
    68  		mxcsrBefore := uint32(0)
    69  		mxcsrAfter := uint32(0)
    70  		stmxcsr(&mxcsrBefore)
    71  		if mxcsrBefore == 0 {
    72  			// goruntime sets mxcsr to 0x1f80 and it never changes
    73  			// the control configuration.
    74  			panic("mxcsr is zero")
    75  		}
    76  		switchOpts.FloatingPointState.SetMXCSR(0)
    77  		if _, err := c.SwitchToUser(
    78  			switchOpts, &si); err == platform.ErrContextInterrupt {
    79  			return true // Retry.
    80  		} else if err != nil {
    81  			t.Errorf("application syscall failed: %v", err)
    82  		}
    83  		stmxcsr(&mxcsrAfter)
    84  		if mxcsrAfter&mxcsrControllMask != mxcsrBefore&mxcsrControllMask {
    85  			t.Errorf("mxcsr = %x (expected %x)", mxcsrBefore, mxcsrAfter)
    86  		}
    87  		return false
    88  	})
    89  }