Commit dc891849 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Michael Ellerman
Browse files

powerpc/kvm/nested: Add helper to walk nested shadow linux page table. 



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: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200505071729.54912-11-aneesh.kumar@linux.ibm.com
parent 4b99412e

arch/powerpc/kvm/book3s_hv_nested.c

+21 −7
Original line number Diff line number Diff line
@@ -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)) {