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Subject[PATCH 5/5] KVM: x86: Set kvm_x86_ops only after ->hardware_setup() completes
Date
Set kvm_x86_ops with the vendor's ops only after ->hardware_setup()
completes to "prevent" using kvm_x86_ops before they are ready, i.e. to
generate a null pointer fault instead of silently consuming unconfigured
state.

An alternative implementation would be to have ->hardware_setup()
return the vendor's ops, but that would require non-trivial refactoring,
and would arguably result in less readable code, e.g. ->hardware_setup()
would need to use ERR_PTR() in multiple locations, and each vendor's
declaration of the runtime ops would be less obvious.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/x86.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index eb36762aa2ce..a9f733c4ca28 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7326,8 +7326,6 @@ int kvm_arch_init(void *opaque)
if (r)
goto out_free_percpu;

- kvm_x86_ops = ops->runtime_ops;
-
kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK,
PT_DIRTY_MASK, PT64_NX_MASK, 0,
PT_PRESENT_MASK, 0, sme_me_mask);
@@ -9588,6 +9586,8 @@ int kvm_arch_hardware_setup(void *opaque)
if (r != 0)
return r;

+ kvm_x86_ops = ops->runtime_ops;
+
cr4_reserved_bits = kvm_host_cr4_reserved_bits(&boot_cpu_data);

if (kvm_has_tsc_control) {
--
2.24.1
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