[PATCH v3 14/22] powerpc/kvm/book3s: Use find_kvm_host_pte in h_enter

From: Aneesh Kumar K.V
Date: Mon Apr 20 2020 - 08:54:35 EST


Since kvmppc_do_h_enter can get called in realmode use low level
arch_spin_lock which is safe to be called in realmode.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
---
arch/powerpc/kvm/book3s_64_mmu_hv.c | 5 ++---
arch/powerpc/kvm/book3s_hv_rm_mmu.c | 22 ++++++----------------
2 files changed, 8 insertions(+), 19 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 121146f5a331..9d48173a8b77 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -281,11 +281,10 @@ static long kvmppc_virtmode_do_h_enter(struct kvm *kvm, unsigned long flags,
{
long ret;

- /* Protect linux PTE lookup from page table destruction */
- rcu_read_lock_sched(); /* this disables preemption too */
+ preempt_disable();
ret = kvmppc_do_h_enter(kvm, flags, pte_index, pteh, ptel,
kvm->mm->pgd, false, pte_idx_ret);
- rcu_read_unlock_sched();
+ preempt_enable();
if (ret == H_TOO_HARD) {
/* this can't happen */
pr_err("KVM: Oops, kvmppc_h_enter returned too hard!\n");
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 03f8347de48b..83e987fecf97 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -210,7 +210,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
pte_t *ptep;
unsigned int writing;
unsigned long mmu_seq;
- unsigned long rcbits, irq_flags = 0;
+ unsigned long rcbits;

if (kvm_is_radix(kvm))
return H_FUNCTION;
@@ -248,17 +248,9 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,

/* Translate to host virtual address */
hva = __gfn_to_hva_memslot(memslot, gfn);
- /*
- * If we had a page table table change after lookup, we would
- * retry via mmu_notifier_retry.
- */
- if (!realmode)
- local_irq_save(irq_flags);
- /*
- * If called in real mode we have MSR_EE = 0. Otherwise
- * we disable irq above.
- */
- ptep = __find_linux_pte(pgdir, hva, NULL, &hpage_shift);
+
+ arch_spin_lock(&kvm->mmu_lock.rlock.raw_lock);
+ ptep = find_kvm_host_pte(kvm, mmu_seq, hva, &hpage_shift);
if (ptep) {
pte_t pte;
unsigned int host_pte_size;
@@ -272,8 +264,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
* to <= host page size, if host is using hugepage
*/
if (host_pte_size < psize) {
- if (!realmode)
- local_irq_restore(flags);
+ arch_spin_unlock(&kvm->mmu_lock.rlock.raw_lock);
return H_PARAMETER;
}
pte = kvmppc_read_update_linux_pte(ptep, writing);
@@ -287,8 +278,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
pa |= gpa & ~PAGE_MASK;
}
}
- if (!realmode)
- local_irq_restore(irq_flags);
+ arch_spin_unlock(&kvm->mmu_lock.rlock.raw_lock);

ptel &= HPTE_R_KEY | HPTE_R_PP0 | (psize-1);
ptel |= pa;
--
2.25.3