@@ -581,27 +581,6 @@ static void __init ms_hyperv_init_platform(void)
if (!(ms_hyperv.features & HV_ACCESS_TSC_INVARIANT))
mark_tsc_unstable("running on Hyper-V");
- /*
- * Mask CET Shadow Stack on SEV-SNP due to a CPUID emulation bug in
- * the paravisor on old Azure SEV-SNP hosts, e.g., 10.0.20348.2867-2-0.
- * Due to the bug, paranoid_xstate_size_valid() in a v6.6 or newer
- * kernel prints a warning "XSAVE consistency problem: size 848 != kernel_size 832"
- * and the kernel disables XSAVE completely; the early 'init' program or
- * any later program may get core-dumped due to "invalid opcode", if
- * they assume XSAVE is available (e.g., it looks like
- * libgnutls.so.30.27.0 tries to unconditionally use XSAVE.
- *
- * Note: the SNP paravisor bug only affects a v6.6+ Linux kernel
- * (CET Shadow Stack is firstly enabled in v6.6) when the VM is a "v5"
- * SNP VM on Azure. A "v6" SNP VM is not affected, and a TDX VM is also
- * not affectd since the versions of paravisor for them are already
- * fixed. The fix for the "v5" VMs would roll out around September or
- * October, 2024.
- */
- if (ms_hyperv.paravisor_present &&
- hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP)
- setup_clear_cpu_cap(X86_FEATURE_SHSTK);
-
hardlockup_detector_disable();
}
BugLink: https://bugs.launchpad.net/bugs/2079841 This reverts commit 8ce273422c040ec77c8bfa58c7d7dbbb570710d0. Signed-off-by: John Cabaj <john.cabaj@canonical.com> --- arch/x86/kernel/cpu/mshyperv.c | 21 --------------------- 1 file changed, 21 deletions(-)