For platform that supports RRSBA (Restricted Return Stack Buffer
Alternate), using retpoline may not be sufficient to guard against branch
history injection or intra-mode branch target injection. RRSBA must
be disabled to prevent CPUs from using alternate predictors for RETs.
Quoting Intel CVE-2022-0001/CVE-2022-0002:
Where software is using retpoline as a mitigation for BHI or intra-mode BTI,
and the processor both enumerates RRSBA and enumerates RRSBA_DIS controls,
it should disable this behavior.
...
Software using retpoline as a mitigation for BHI or intra-mode BTI should use
these new indirect predictor controls to disable alternate predictors for RETs.
See: https://www.intel.com/content/www/us/en/developer/articles/technical/
software-security-guidance/technical-documentation/branch-history-injection.html
Tracked-On: #7907
Signed-off-by: Yifan Liu <yifan1.liu@intel.com>
Modified the copyright year range in code, and corrected "int32_tel"
into "Intel" in two "hypervisor/include/debug/profiling.h" and
"hypervisor/include/debug/profiling_internal.h".
Tracked-On: #7559
Signed-off-by: Ziheng Li <ziheng.li@intel.com>
Many of the license and Intel copyright headers include the "All rights
reserved" string. It is not relevant in the context of the BSD-3-Clause
license that the code is released under. This patch removes those strings
throughout the code (hypervisor, devicemodel and misc).
Tracked-On: #7254
Signed-off-by: Geoffroy Van Cutsem <geoffroy.vancutsem@intel.com>
TPAUSE, UMONITOR or UMWAIT instructions execution in guest VM cause
a #UD if "enable user wait and pause" (bit 26) of VMX_PROCBASED_CTLS2
is not set. To fix this issue, set the bit 26 of VMX_PROCBASED_CTLS2.
Besides, these WAITPKG instructions uses MSR_IA32_UMWAIT_CONTROL. So
load corresponding vMSR value during context switch in of a vCPU.
Please note, the TPAUSE or UMWAIT instruction causes a VM exit if the
"RDTSC exiting" and "enable user wait and pause" are both 1. In ACRN
hypervisor, "RDTSC exiting" is always 0. So TPAUSE or UMWAIT doesn't
cause a VM exit.
Performance impact:
MSR_IA32_UMWAIT_CONTROL read costs ~19 cycles;
MSR_IA32_UMWAIT_CONTROL write costs ~63 cycles.
Tracked-On: #6006
Signed-off-by: Shuo A Liu <shuo.a.liu@intel.com>
Instead of "#include <x86/foo.h>", use "#include <asm/foo.h>".
In other words, we are adopting the same practice in Linux kernel.
Tracked-On: #5920
Signed-off-by: Liang Yi <yi.liang@intel.com>
Reviewed-by: Jason Chen CJ <jason.cj.chen@intel.com>
