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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>, npiggin@gmail.com
Subject: [PATCH v4 10/22] powerpc/kvm/nested: Add helper to walk nested shadow linux page table.
Date: Tue,  5 May 2020 12:47:17 +0530	[thread overview]
Message-ID: <20200505071729.54912-11-aneesh.kumar@linux.ibm.com> (raw)
In-Reply-To: <20200505071729.54912-1-aneesh.kumar@linux.ibm.com>

The locking rules for walking nested shadow linux page table is different from process
scoped table. Hence add a helper for nested page table walk and also
add check whether we are holding the right locks.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/kvm/book3s_hv_nested.c | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 7f1fc5db13ea..b2cc3eaec618 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -750,6 +750,24 @@ static struct kvm_nested_guest *kvmhv_find_nested(struct kvm *kvm, int lpid)
 	return kvm->arch.nested_guests[lpid];
 }
 
+static pte_t *find_kvm_nested_guest_pte(struct kvm *kvm, unsigned long lpid,
+					unsigned long ea, unsigned *hshift)
+{
+	struct kvm_nested_guest *gp;
+	pte_t *pte;
+
+	gp = kvmhv_find_nested(kvm, lpid);
+	if (!gp)
+		return NULL;
+
+	VM_WARN(!spin_is_locked(&kvm->mmu_lock),
+		"%s called with kvm mmu_lock not held \n", __func__);
+	pte = __find_linux_pte(gp->shadow_pgtable, ea, NULL, hshift);
+
+	return pte;
+}
+
+
 static inline bool kvmhv_n_rmap_is_equal(u64 rmap_1, u64 rmap_2)
 {
 	return !((rmap_1 ^ rmap_2) & (RMAP_NESTED_LPID_MASK |
@@ -792,19 +810,15 @@ static void kvmhv_update_nest_rmap_rc(struct kvm *kvm, u64 n_rmap,
 				      unsigned long clr, unsigned long set,
 				      unsigned long hpa, unsigned long mask)
 {
-	struct kvm_nested_guest *gp;
 	unsigned long gpa;
 	unsigned int shift, lpid;
 	pte_t *ptep;
 
 	gpa = n_rmap & RMAP_NESTED_GPA_MASK;
 	lpid = (n_rmap & RMAP_NESTED_LPID_MASK) >> RMAP_NESTED_LPID_SHIFT;
-	gp = kvmhv_find_nested(kvm, lpid);
-	if (!gp)
-		return;
 
 	/* Find the pte */
-	ptep = __find_linux_pte(gp->shadow_pgtable, gpa, NULL, &shift);
+	ptep = find_kvm_nested_guest_pte(kvm, lpid, gpa, &shift);
 	/*
 	 * If the pte is present and the pfn is still the same, update the pte.
 	 * If the pfn has changed then this is a stale rmap entry, the nested
@@ -854,7 +868,7 @@ static void kvmhv_remove_nest_rmap(struct kvm *kvm, u64 n_rmap,
 		return;
 
 	/* Find and invalidate the pte */
-	ptep = __find_linux_pte(gp->shadow_pgtable, gpa, NULL, &shift);
+	ptep = find_kvm_nested_guest_pte(kvm, lpid, gpa, &shift);
 	/* Don't spuriously invalidate ptes if the pfn has changed */
 	if (ptep && pte_present(*ptep) && ((pte_val(*ptep) & mask) == hpa))
 		kvmppc_unmap_pte(kvm, ptep, gpa, shift, NULL, gp->shadow_lpid);
@@ -921,7 +935,7 @@ static bool kvmhv_invalidate_shadow_pte(struct kvm_vcpu *vcpu,
 	int shift;
 
 	spin_lock(&kvm->mmu_lock);
-	ptep = __find_linux_pte(gp->shadow_pgtable, gpa, NULL, &shift);
+	ptep = find_kvm_nested_guest_pte(kvm, gp->l1_lpid, gpa, &shift);
 	if (!shift)
 		shift = PAGE_SHIFT;
 	if (ptep && pte_present(*ptep)) {
-- 
2.26.2


  parent reply	other threads:[~2020-05-05  7:47 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-05  7:17 [PATCH v4 00/22] Avoid IPI while updating page table entries Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 01/22] powerpc/pkeys: Avoid using lockless page table walk Aneesh Kumar K.V
2020-05-13  8:49   ` Michael Ellerman
2020-05-05  7:17 ` [PATCH v4 02/22] powerpc/pkeys: Check vma before returning key fault error to the user Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 03/22] powerpc/mm/hash64: use _PAGE_PTE when checking for pte_present Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 04/22] powerpc/hash64: Restrict page table lookup using init_mm with __flush_hash_table_range Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 05/22] powerpc/book3s64/hash: Use the pte_t address from the caller Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 06/22] powerpc/mce: Don't reload pte val in addr_to_pfn Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 07/22] powerpc/perf/callchain: Use __get_user_pages_fast in read_user_stack_slow Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 08/22] powerpc/kvm/book3s: switch from raw_spin_*lock to arch_spin_lock Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 09/22] powerpc/kvm/book3s: Add helper to walk partition scoped linux page table Aneesh Kumar K.V
2020-05-28  1:43   ` Paul Mackerras
2020-05-28  6:01     ` Aneesh Kumar K.V
2020-05-28  7:25       ` Paul Mackerras
2020-05-05  7:17 ` Aneesh Kumar K.V [this message]
2020-05-05  7:17 ` [PATCH v4 11/22] powerpc/kvm/book3s: Use kvm helpers to walk shadow or secondary table Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 12/22] powerpc/kvm/book3s: Add helper for host page table walk Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 13/22] powerpc/kvm/book3s: Use find_kvm_host_pte in page fault handler Aneesh Kumar K.V
2020-05-06  3:29   ` kbuild test robot
2020-05-05  7:17 ` [PATCH v4 14/22] powerpc/kvm/book3s: Use find_kvm_host_pte in h_enter Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 15/22] powerpc/kvm/book3s: use find_kvm_host_pte in pute_tce functions Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 16/22] powerpc/kvm/book3s: Avoid using rmap to protect parallel page table update Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 17/22] powerpc/kvm/book3s: use find_kvm_host_pte in kvmppc_book3s_instantiate_page Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 18/22] powerpc/kvm/book3s: Use find_kvm_host_pte in kvmppc_get_hpa Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 19/22] powerpc/kvm/book3s: Use pte_present instead of opencoding _PAGE_PRESENT check Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 20/22] powerpc/mm/book3s64: Avoid sending IPI on clearing PMD Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 21/22] mm: change pmdp_huge_get_and_clear_full take vm_area_struct as arg Aneesh Kumar K.V
2020-05-05  7:17 ` [PATCH v4 22/22] powerpc/mm/book3s64: Fix MADV_DONTNEED and parallel page fault race Aneesh Kumar K.V

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