* Akihiro Suda <suda.gitsendemail@xxxxxxxxx> wrote:
> Even when X86_FEATURE_PKU and X86_FEATURE_OSPKE are available,
> XFEATURE_PKRU can be missing.
> In such a case, pkeys has to be disabled to avoid hanging up.
>
> WARNING: CPU: 0 PID: 1 at arch/x86/kernel/fpu/xstate.c:1003 get_xsave_addr_user+0x28/0x40
> (...)
> Call Trace:
> <TASK>
> ? get_xsave_addr_user+0x28/0x40
> ? __warn.cold+0x8e/0xea
> ? get_xsave_addr_user+0x28/0x40
> ? report_bug+0xff/0x140
> ? handle_bug+0x3b/0x70
> ? exc_invalid_op+0x17/0x70
> ? asm_exc_invalid_op+0x1a/0x20
> ? get_xsave_addr_user+0x28/0x40
> copy_fpstate_to_sigframe+0x1be/0x380
> ? __put_user_8+0x11/0x20
> get_sigframe+0xf1/0x280
> x64_setup_rt_frame+0x67/0x2c0
> arch_do_signal_or_restart+0x1b3/0x240
> syscall_exit_to_user_mode+0xb0/0x130
> do_syscall_64+0xab/0x1a0
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> This fix is known to be needed on Apple Virtualization.
> Tested with macOS 13.5.2 running on MacBook Pro 2020 with
> Intel(R) Core(TM) i7-1068NG7 CPU @ 2.30GHz.
>
> Fixes: 70044df250d0 ("x86/pkeys: Update PKRU to enable all pkeys before XSAVE")
> Link: https://lore.kernel.org/regressions/CAG8fp8QvH71Wi_y7b7tgFp7knK38rfrF7rRHh-gFKqeS0gxY6Q@xxxxxxxxxxxxxx/T/#u
> Link: https://github.com/lima-vm/lima/issues/3334
>
> Signed-off-by: Akihiro Suda <akihiro.suda.cz@xxxxxxxxxxxxx>
> ---
> arch/x86/kernel/cpu/common.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index e9464fe411ac..4c2c268af214 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -517,7 +517,8 @@ static bool pku_disabled;
> static __always_inline void setup_pku(struct cpuinfo_x86 *c)
> {
> if (c == &boot_cpu_data) {
> - if (pku_disabled || !cpu_feature_enabled(X86_FEATURE_PKU))
> + if (pku_disabled || !cpu_feature_enabled(X86_FEATURE_PKU) ||
> + !cpu_has_xfeatures(XFEATURE_PKRU, NULL))
> return;
Note that silent quirks are counterproductive, as they don't give VM
vendors any incentives to fix their VM for such bugs.
So I changed your quirk to be:
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -519,6 +519,17 @@ static __always_inline void setup_pku(struct cpuinfo_x86 *c)
if (c == &boot_cpu_data) {
if (pku_disabled || !cpu_feature_enabled(X86_FEATURE_PKU))
return;
+ if (!cpu_has_xfeatures(XFEATURE_PKRU, NULL)) {
+ /*
+ * Missing XFEATURE_PKRU is not really a valid CPU
+ * configuration at this point, but apparently
+ * Apple Virtualization is affected by this,
+ * so return with a FW warning instead of crashing
+ * the bootup:
+ */
+ WARN_ONCE(1, FW_BUG "Invalid XFEATURE_PKRU configuration.\n");
+ return;
+ }
/*
* Setting CR4.PKE will cause the X86_FEATURE_OSPKE cpuid
* bit to be set. Enforce it.
This is noisy in the syslog, but it's a WARN_ONCE() and it doesn't
crash the bootup.
Thanks,
Ingo
