diff options
| author | Adin Scannell <ascannell@google.com> | 2018-07-16 22:02:03 -0700 |
|---|---|---|
| committer | Shentubot <shentubot@google.com> | 2018-07-16 22:02:58 -0700 |
| commit | 29e00c943a61dfcfd4ac8d3f6f526eab641c44a6 (patch) | |
| tree | f7cdb0c59c8363b3a4e5737e17b1b4e423bfc05a /pkg/sentry/platform/ring0 | |
| parent | 14d06064d26b1cd9e2ccad08ebe997e704092eb8 (diff) | |
Add CPUID faulting for ptrace and KVM.
PiperOrigin-RevId: 204858314
Change-Id: I8252bf8de3232a7a27af51076139b585e73276d4
Diffstat (limited to 'pkg/sentry/platform/ring0')
| -rw-r--r-- | pkg/sentry/platform/ring0/kernel_amd64.go | 22 | ||||
| -rw-r--r-- | pkg/sentry/platform/ring0/x86.go | 14 |
2 files changed, 31 insertions, 5 deletions
diff --git a/pkg/sentry/platform/ring0/kernel_amd64.go b/pkg/sentry/platform/ring0/kernel_amd64.go index 117e86104..0d2b0f7dc 100644 --- a/pkg/sentry/platform/ring0/kernel_amd64.go +++ b/pkg/sentry/platform/ring0/kernel_amd64.go @@ -163,7 +163,6 @@ func IsCanonical(addr uint64) bool { // the case for amd64, but may not be the case for other architectures. // // Precondition: the Rip, Rsp, Fs and Gs registers must be canonical. - // //go:nosplit func (c *CPU) SwitchToUser(switchOpts SwitchOpts) (vector Vector) { @@ -237,6 +236,27 @@ func start(c *CPU) { wrmsr(_MSR_CSTAR, kernelFunc(sysenter)) } +// SetCPUIDFaulting sets CPUID faulting per the boolean value. +// +// True is returned if faulting could be set. +// +//go:nosplit +func SetCPUIDFaulting(on bool) bool { + // Per the SDM (Vol 3, Table 2-43), PLATFORM_INFO bit 31 denotes support + // for CPUID faulting, and we enable and disable via the MISC_FEATURES MSR. + if rdmsr(_MSR_PLATFORM_INFO)&_PLATFORM_INFO_CPUID_FAULT != 0 { + features := rdmsr(_MSR_MISC_FEATURES) + if on { + features |= _MISC_FEATURE_CPUID_TRAP + } else { + features &^= _MISC_FEATURE_CPUID_TRAP + } + wrmsr(_MSR_MISC_FEATURES, features) + return true // Setting successful. + } + return false +} + // ReadCR2 reads the current CR2 value. // //go:nosplit diff --git a/pkg/sentry/platform/ring0/x86.go b/pkg/sentry/platform/ring0/x86.go index 3d437a77c..f489fcecb 100644 --- a/pkg/sentry/platform/ring0/x86.go +++ b/pkg/sentry/platform/ring0/x86.go @@ -50,10 +50,16 @@ const ( _EFER_LMA = 0x400 _EFER_NX = 0x800 - _MSR_STAR = 0xc0000081 - _MSR_LSTAR = 0xc0000082 - _MSR_CSTAR = 0xc0000083 - _MSR_SYSCALL_MASK = 0xc0000084 + _MSR_STAR = 0xc0000081 + _MSR_LSTAR = 0xc0000082 + _MSR_CSTAR = 0xc0000083 + _MSR_SYSCALL_MASK = 0xc0000084 + _MSR_PLATFORM_INFO = 0xce + _MSR_MISC_FEATURES = 0x140 + + _PLATFORM_INFO_CPUID_FAULT = 1 << 31 + + _MISC_FEATURE_CPUID_TRAP = 0x1 ) const ( |