[PATCH v3 06/21] KVM: X86: Don't take srcu lock in init_rmode_identity_map()

From: Peter Xu
Date: Thu Jan 09 2020 - 09:57:56 EST


We've already got the slots_lock, so we should be safe.

Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
arch/x86/kvm/vmx/vmx.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b5a0c2e05825..7add2fc8d8e9 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -3475,7 +3475,7 @@ static int init_rmode_tss(struct kvm *kvm)
static int init_rmode_identity_map(struct kvm *kvm)
{
struct kvm_vmx *kvm_vmx = to_kvm_vmx(kvm);
- int i, idx, r = 0;
+ int i, r = 0;
kvm_pfn_t identity_map_pfn;
u32 tmp;

@@ -3483,7 +3483,7 @@ static int init_rmode_identity_map(struct kvm *kvm)
mutex_lock(&kvm->slots_lock);

if (likely(kvm_vmx->ept_identity_pagetable_done))
- goto out2;
+ goto out;

if (!kvm_vmx->ept_identity_map_addr)
kvm_vmx->ept_identity_map_addr = VMX_EPT_IDENTITY_PAGETABLE_ADDR;
@@ -3492,9 +3492,8 @@ static int init_rmode_identity_map(struct kvm *kvm)
r = __x86_set_memory_region(kvm, IDENTITY_PAGETABLE_PRIVATE_MEMSLOT,
kvm_vmx->ept_identity_map_addr, PAGE_SIZE);
if (r < 0)
- goto out2;
+ goto out;

- idx = srcu_read_lock(&kvm->srcu);
r = kvm_clear_guest_page(kvm, identity_map_pfn, 0, PAGE_SIZE);
if (r < 0)
goto out;
@@ -3510,9 +3509,6 @@ static int init_rmode_identity_map(struct kvm *kvm)
kvm_vmx->ept_identity_pagetable_done = true;

out:
- srcu_read_unlock(&kvm->srcu, idx);
-
-out2:
mutex_unlock(&kvm->slots_lock);
return r;
}
--
2.24.1