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From: David Gibson <david@gibson.dropbear.id.au>
To: paulus@samba.org, sjitindarsingh@gmail.com
Cc: benh@kernel.crashing.org, thuth@redhat.com, lvivier@redhat.com,
	linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	David Gibson <david@gibson.dropbear.id.au>
Subject: [PATCHv2 08/11] powerpc/kvm: Create kvmppc_unmap_hpte_helper()
Date: Tue, 20 Dec 2016 16:49:04 +1100	[thread overview]
Message-ID: <20161220054907.9204-9-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20161220054907.9204-1-david@gibson.dropbear.id.au>

The kvm_unmap_rmapp() function, called from certain MMU notifiers, is used
to force all guest mappings of a particular host page to be set ABSENT, and
removed from the reverse mappings.

For HPT resizing, we will have some cases where we want to set just a
single guest HPTE ABSENT and remove its reverse mappings.  To prepare with
this, we split out the logic from kvm_unmap_rmapp() to evict a single HPTE,
moving it to a new helper function.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 arch/powerpc/kvm/book3s_64_mmu_hv.c | 77 +++++++++++++++++++++----------------
 1 file changed, 44 insertions(+), 33 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 2765d04..74e909a 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -738,13 +738,53 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
 	return kvm_handle_hva_range(kvm, hva, hva + 1, handler);
 }
 
+/* Must be called with both HPTE and rmap locked */
+static void kvmppc_unmap_hpte(struct kvm *kvm, unsigned long i,
+			      unsigned long *rmapp, unsigned long gfn)
+{
+	__be64 *hptep = (__be64 *) (kvm->arch.hpt.virt + (i << 4));
+	struct revmap_entry *rev = kvm->arch.hpt.rev;
+	unsigned long j, h;
+	unsigned long ptel, psize, rcbits;
+
+	j = rev[i].forw;
+	if (j == i) {
+		/* chain is now empty */
+		*rmapp &= ~(KVMPPC_RMAP_PRESENT | KVMPPC_RMAP_INDEX);
+	} else {
+		/* remove i from chain */
+		h = rev[i].back;
+		rev[h].forw = j;
+		rev[j].back = h;
+		rev[i].forw = rev[i].back = i;
+		*rmapp = (*rmapp & ~KVMPPC_RMAP_INDEX) | j;
+	}
+
+	/* Now check and modify the HPTE */
+	ptel = rev[i].guest_rpte;
+	psize = hpte_page_size(be64_to_cpu(hptep[0]), ptel);
+	if ((be64_to_cpu(hptep[0]) & HPTE_V_VALID) &&
+	    hpte_rpn(ptel, psize) == gfn) {
+		hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
+		kvmppc_invalidate_hpte(kvm, hptep, i);
+		hptep[1] &= ~cpu_to_be64(HPTE_R_KEY_HI | HPTE_R_KEY_LO);
+		/* Harvest R and C */
+		rcbits = be64_to_cpu(hptep[1]) & (HPTE_R_R | HPTE_R_C);
+		*rmapp |= rcbits << KVMPPC_RMAP_RC_SHIFT;
+		if (rcbits & HPTE_R_C)
+			kvmppc_update_rmap_change(rmapp, psize);
+		if (rcbits & ~rev[i].guest_rpte) {
+			rev[i].guest_rpte = ptel | rcbits;
+			note_hpte_modification(kvm, &rev[i]);
+		}
+	}
+}
+
 static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
 			   unsigned long gfn)
 {
-	struct revmap_entry *rev = kvm->arch.hpt.rev;
-	unsigned long h, i, j;
+	unsigned long i;
 	__be64 *hptep;
-	unsigned long ptel, psize, rcbits;
 
 	for (;;) {
 		lock_rmap(rmapp);
@@ -767,37 +807,8 @@ static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp,
 				cpu_relax();
 			continue;
 		}
-		j = rev[i].forw;
-		if (j == i) {
-			/* chain is now empty */
-			*rmapp &= ~(KVMPPC_RMAP_PRESENT | KVMPPC_RMAP_INDEX);
-		} else {
-			/* remove i from chain */
-			h = rev[i].back;
-			rev[h].forw = j;
-			rev[j].back = h;
-			rev[i].forw = rev[i].back = i;
-			*rmapp = (*rmapp & ~KVMPPC_RMAP_INDEX) | j;
-		}
 
-		/* Now check and modify the HPTE */
-		ptel = rev[i].guest_rpte;
-		psize = hpte_page_size(be64_to_cpu(hptep[0]), ptel);
-		if ((be64_to_cpu(hptep[0]) & HPTE_V_VALID) &&
-		    hpte_rpn(ptel, psize) == gfn) {
-			hptep[0] |= cpu_to_be64(HPTE_V_ABSENT);
-			kvmppc_invalidate_hpte(kvm, hptep, i);
-			hptep[1] &= ~cpu_to_be64(HPTE_R_KEY_HI | HPTE_R_KEY_LO);
-			/* Harvest R and C */
-			rcbits = be64_to_cpu(hptep[1]) & (HPTE_R_R | HPTE_R_C);
-			*rmapp |= rcbits << KVMPPC_RMAP_RC_SHIFT;
-			if (rcbits & HPTE_R_C)
-				kvmppc_update_rmap_change(rmapp, psize);
-			if (rcbits & ~rev[i].guest_rpte) {
-				rev[i].guest_rpte = ptel | rcbits;
-				note_hpte_modification(kvm, &rev[i]);
-			}
-		}
+		kvmppc_unmap_hpte(kvm, i, rmapp, gfn);
 		unlock_rmap(rmapp);
 		__unlock_hpte(hptep, be64_to_cpu(hptep[0]));
 	}
-- 
2.9.3

  parent reply	other threads:[~2016-12-20  5:51 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-20  5:48 [PATCHv2 00/11] KVM implementation of PAPR HPT resizing extension David Gibson
2016-12-20  5:48 ` [PATCHv2 01/11] Documentation: Correct duplicate section number in kvm/api.txt David Gibson
2016-12-20  5:48   ` David Gibson
2016-12-20  5:48 ` [PATCHv2 02/11] powerpc/kvm: HPT resizing documentation and reserved numbers David Gibson
2016-12-20  5:48 ` [PATCHv2 03/11] powerpc/kvm: Rename kvm_alloc_hpt() for clarity David Gibson
2016-12-20  5:49 ` [PATCHv2 04/11] powerpc/kvm: Gather HPT related variables into sub-structure David Gibson
2016-12-20  5:49 ` [PATCHv2 05/11] powerpc/kvm: Don't store values derivable from HPT order David Gibson
2016-12-20  5:49 ` [PATCHv2 06/11] powerpc/kvm: Split HPT allocation from activation David Gibson
2016-12-20  5:49 ` [PATCHv2 07/11] powerpc/kvm: Allow KVM_PPC_ALLOCATE_HTAB ioctl() to change HPT size David Gibson
2016-12-20  5:49 ` David Gibson [this message]
2016-12-20  5:49 ` [PATCHv2 09/11] powerpc/kvm: Outline of KVM-HV HPT resizing implementation David Gibson
2016-12-20  5:49 ` [PATCHv2 10/11] powerpc/kvm: " David Gibson
2016-12-20  5:49 ` [PATCHv2 11/11] powerpc/kvm: Advertise availablity of HPT resizing on KVM HV David Gibson
2017-01-31 22:18 ` [PATCHv2 00/11] KVM implementation of PAPR HPT resizing extension Paul Mackerras
2017-02-01  4:56   ` David Gibson
2017-02-01  5:07     ` Paul Mackerras

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