Timekeeping Virtualization for X86-Based Architectures
ウェブVMX provides conditional trapping of RDTSC, RDMSR, WRMSR and RDTSCP instructions, which is enough for full virtualization of TSC in any manner. In addition, VMX allows passing through the host TSC plus an additional TSC
Why is RDTSC a virtualized instruction on modern processors?
ウェブ2011年10月12日 · Its common to use RDTSC to get fine-grained timing information, where the overhead of a virtualization trap would be quite significant. Most common use is to have two RDTSC instructions with a small amount of code between
xuwd1/rdtsc-notes - GitHub
ウェブOn x86 platforms the rdtsc and rdtscp instructions gave us the ability to access a internal 64-bit hardware time stamp counter TSC (Time Stamp Counter) that is reset to zero at boot time and since then increments at a certain frequency (ideally at the same rate as the processor clock speed), which can be very useful for conducting microbenchmarks.
c - RDTSCP versus RDTSC + CPUID - Stack Overflow
ウェブ2014年12月30日 · RDTSC + CPUID (in reverse order, here) to flush the pipeline, and incurred up to a 60x overhead (!) on a Virtual Machine (my working environment) due to hypercalls and whatnot. This is both with and without HW Virtualization
An introduction to timekeeping in Linux VMs | Opensource.com
ウェブ2017年6月8日 · CLOCK_REALTIME clock gives the time passed since January 1, 1970. This clock is affected by NTP adjustments and can jump forward and backward when a system administrator adjusts system time. CLOCK_MONOTONIC clock gives the time since a fixed starting point—usually since you booted the system.
Difference between rdtscp, rdtsc : memory and cpuid / rdtsc?
ウェブ2012年9月28日 · So we can use either of these two options to prevent reordering: 2: This is a call to cpuid and then rdtsc. cpuid is a serializing call. volatile int dont_remove __attribute__((unused)); // volatile to stop optimizing. unsigned tmp; __cpuid(0, tmp, tmp, tmp, tmp); // cpuid is a serialising call.
RDTSC | x86 Instruction Set Reference
ウェブ2019年4月18日 · Description. Loads the current value of the processor's time-stamp counter into the EDX:EAX registers. The time-stamp counter is contained in a 64-bit MSR. The high-order 32 bits of the MSR are loaded into the EDX register, and the low-order 32 bits are loaded into the EAX register.
Resurrecting anti-virtualization and anti-debugging: Unhooking ...
ウェブ2021年3月1日 · This is accomplished in ANTI by using the RDTSC instruction and the NtQueryPerformanceCounter Native API function. The RDTSC (Read Time Stamp Counter) instruction returns the current value of the timestamp counter from the processor, while NtQueryPerformanceCounter retrieves the current value of the performance …
Clocks, Timers and Virtualization :: silly onions ...
ウェブ2020年7月12日 · In both Intel VT-x and AMD SVM, the TSC can be fully virtualized by trapping the RDTSC, RDMSR, WRMSR and RDTSCP instructions [5]. Also, it is possible to pass through the host TSC to the virtual machine. Both trapping and
ウェブIn this paper, we present analysis results for RDTSC usage collected from more than 200,000 malware files. In this analysis, malware programs are searched for closely placed pairs of RDTSCs; then, code fragments surrounding these pairs are extracted.
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