On 3/4/22 20:48, isaku.yamahata@xxxxxxxxx wrote:
+ if (enable_ept) {
+ const u64 init_value = enable_tdx ? VMX_EPT_SUPPRESS_VE_BIT : 0ull;
kvm_mmu_set_ept_masks(enable_ept_ad_bits,
- cpu_has_vmx_ept_execute_only());
+ cpu_has_vmx_ept_execute_only(), init_value);
+ kvm_mmu_set_spte_init_value(init_value);
+ }
I think kvm-intel.ko should use VMX_EPT_SUPPRESS_VE_BIT unconditionally
as the init value. The bit is ignored anyway if the "EPT-violation #VE"
execution control is 0. Otherwise looks good, but I have a couple more
crazy ideas:
1) there could even be a test mode where KVM enables the execution
control, traps #VE in the exception bitmap, and shouts loudly if it gets
a #VE. That might avoid hard-to-find bugs due to forgetting about
VMX_EPT_SUPPRESS_VE_BIT.
2) or even, perhaps the init_value for the TDP MMU could set bit 63
_unconditionally_, because KVM always sets the NX bit on AMD hardware.
That would remove the whole infrastructure to keep shadow_init_value,
because it would be constant 0 in mmu.c and constant BIT(63) in tdp_mmu.c.
Sean, what do you think?
Paolo
