Add a macro to handle kicking vCPUs out of the guest and retrying
SEAMCALLs on -EBUSY instead of providing small helpers to be used by each
SEAMCALL. Wrapping the SEAMCALLs in a macro makes it a little harder to
tease out which SEAMCALL is being made, but significantly reduces the
amount of copy+paste code and makes it all but impossible to leave an
elevated wait_for_sept_zap.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/vmx/tdx.c | 72 ++++++++++++++----------------------------
1 file changed, 23 insertions(+), 49 deletions(-)
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index aa740eeb1c2a..d6c9defad9cd 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -313,25 +313,24 @@ static void tdx_clear_page(struct page *page)
__mb();
}
-static void tdx_no_vcpus_enter_start(struct kvm *kvm)
-{
- struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
-
- lockdep_assert_held_write(&kvm->mmu_lock);
-
- WRITE_ONCE(kvm_tdx->wait_for_sept_zap, true);
-
- kvm_make_all_cpus_request(kvm, KVM_REQ_OUTSIDE_GUEST_MODE);
-}
-
-static void tdx_no_vcpus_enter_stop(struct kvm *kvm)
-{
- struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
-
- lockdep_assert_held_write(&kvm->mmu_lock);
-
- WRITE_ONCE(kvm_tdx->wait_for_sept_zap, false);
-}
+#define tdh_do_no_vcpus(tdh_func, kvm, args...) \
+({ \
+ struct kvm_tdx *__kvm_tdx = to_kvm_tdx(kvm); \
+ u64 __err; \
+ \
+ lockdep_assert_held_write(&kvm->mmu_lock); \
+ \
+ __err = tdh_func(args); \
+ if (unlikely(tdx_operand_busy(__err))) { \
+ WRITE_ONCE(__kvm_tdx->wait_for_sept_zap, true); \
+ kvm_make_all_cpus_request(kvm, KVM_REQ_OUTSIDE_GUEST_MODE); \
+ \
+ __err = tdh_func(args); \
+ \
+ WRITE_ONCE(__kvm_tdx->wait_for_sept_zap, false); \
+ } \
+ __err; \
+})
/* TDH.PHYMEM.PAGE.RECLAIM is allowed only when destroying the TD. */
static int __tdx_reclaim_page(struct page *page)
@@ -1714,14 +1713,7 @@ static void tdx_track(struct kvm *kvm)
if (unlikely(kvm_tdx->state != TD_STATE_RUNNABLE))
return;
- err = tdh_mem_track(&kvm_tdx->td);
- if (unlikely(tdx_operand_busy(err))) {
- /* After no vCPUs enter, the second retry is expected to succeed */
- tdx_no_vcpus_enter_start(kvm);
- err = tdh_mem_track(&kvm_tdx->td);
- tdx_no_vcpus_enter_stop(kvm);
- }
-
+ err = tdh_do_no_vcpus(tdh_mem_track, kvm, &kvm_tdx->td);
TDX_BUG_ON(err, TDH_MEM_TRACK, kvm);
kvm_make_all_cpus_request(kvm, KVM_REQ_OUTSIDE_GUEST_MODE);
@@ -1773,14 +1765,8 @@ static void tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
if (KVM_BUG_ON(level != PG_LEVEL_4K, kvm))
return;
- err = tdh_mem_range_block(&kvm_tdx->td, gpa, tdx_level, &entry, &level_state);
- if (unlikely(tdx_operand_busy(err))) {
- /* After no vCPUs enter, the second retry is expected to succeed */
- tdx_no_vcpus_enter_start(kvm);
- err = tdh_mem_range_block(&kvm_tdx->td, gpa, tdx_level, &entry, &level_state);
- tdx_no_vcpus_enter_stop(kvm);
- }
-
+ err = tdh_do_no_vcpus(tdh_mem_range_block, kvm, &kvm_tdx->td, gpa,
+ tdx_level, &entry, &level_state);
if (TDX_BUG_ON_2(err, TDH_MEM_RANGE_BLOCK, entry, level_state, kvm))
return;
@@ -1795,20 +1781,8 @@ static void tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
* with other vcpu sept operation.
* Race with TDH.VP.ENTER due to (0-step mitigation) and Guest TDCALLs.
*/
- err = tdh_mem_page_remove(&kvm_tdx->td, gpa, tdx_level, &entry,
- &level_state);
-
- if (unlikely(tdx_operand_busy(err))) {
- /*
- * The second retry is expected to succeed after kicking off all
- * other vCPUs and prevent them from invoking TDH.VP.ENTER.
- */
- tdx_no_vcpus_enter_start(kvm);
- err = tdh_mem_page_remove(&kvm_tdx->td, gpa, tdx_level, &entry,
- &level_state);
- tdx_no_vcpus_enter_stop(kvm);
- }
-
+ err = tdh_do_no_vcpus(tdh_mem_page_remove, kvm, &kvm_tdx->td, gpa,
+ tdx_level, &entry, &level_state);
if (TDX_BUG_ON_2(err, TDH_MEM_PAGE_REMOVE, entry, level_state, kvm))
return;
--
2.51.0.318.gd7df087d1a-goog
