On 11.06.2021 12:03, Borislav Petkov wrote:
On Wed, Jun 09, 2021 at 02:13:38PM -0700, Pawan Gupta wrote:@@ -114,6 +127,26 @@ void __init tsx_init(void) tsx_ctrl_state = TSX_CTRL_ENABLE; } + /* + * Hardware will always abort a TSX transaction if both CPUID bits + * RTM_ALWAYS_ABORT and TSX_FORCE_ABORT are enumerated. In this case it + * is better not to enumerate CPUID.RTM and CPUID.HLE bits. Clear them + * here. + */ + if (boot_cpu_has(X86_FEATURE_RTM_ALWAYS_ABORT) && + boot_cpu_has(X86_FEATURE_TSX_FORCE_ABORT)) { + tsx_ctrl_state = TSX_CTRL_RTM_ALWAYS_ABORT; + tsx_clear_cpuid(); + setup_clear_cpu_cap(X86_FEATURE_RTM); + setup_clear_cpu_cap(X86_FEATURE_HLE); + return; + }Why isn't this happening as the first thing on entry in that tsx_init() function? IOW, there's no point to noodle through cmdline options etc if the hardware will always abort transactions.
Because the next patch is adding tsx=fake cmdline, for that this code needs to be executed after cmdline parsing. I wanted to avoid the churn to move this code between patches. But, I see your comment for 4/4 i.e. tsx=fake may not be needed. It was added after an internal test failure. tsx=fake is really for a corner case and if that patch goes away it would make sense to move the code in question here before cmdline parsing. Thanks, Pawan
