From: Sean Christopherson <sean.j.christopherson@intel.com>
To: "James Hogan" <jhogan@kernel.org>,
"Paul Mackerras" <paulus@ozlabs.org>,
"Christian Borntraeger" <borntraeger@de.ibm.com>,
"Janosch Frank" <frankja@linux.ibm.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Marc Zyngier" <marc.zyngier@arm.com>
Cc: David Hildenbrand <david@redhat.com>,
Cornelia Huck <cohuck@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry@arm.com>,
Suzuki K Pouloze <suzuki.poulose@arm.com>,
linux-mips@vger.kernel.org, kvm-ppc@vger.kernel.org,
kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org
Subject: [PATCH 09/13] KVM: Clean up local variable usage in __kvm_set_memory_region()
Date: Wed, 11 Sep 2019 11:50:34 -0700 [thread overview]
Message-ID: <20190911185038.24341-10-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20190911185038.24341-1-sean.j.christopherson@intel.com>
Clean up __kvm_set_memory_region() to achieve several goals:
- Remove local variables that serve no real purpose
- Improve the readability of the code
- Better show the relationship between the 'old' and 'new' memslot
- Prepare for dynamically sizing memslots.
Note, using 'tmp' to hold the initial memslot is not strictly necessary
at this juncture, e.g. 'old' could be directly copied from
id_to_memslot(), but keep the pointer usage as id_to_memslot() will be
able to return a NULL pointer once memslots are dynamically sized.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
virt/kvm/kvm_main.c | 47 +++++++++++++++++++++++----------------------
1 file changed, 24 insertions(+), 23 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 8f2f4ee32f3e..0e46524487cc 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -995,13 +995,11 @@ static int kvm_delete_memslot(struct kvm *kvm,
int __kvm_set_memory_region(struct kvm *kvm,
const struct kvm_userspace_memory_region *mem)
{
- int r;
- gfn_t base_gfn;
- unsigned long npages;
- struct kvm_memory_slot *slot;
struct kvm_memory_slot old, new;
- int as_id, id;
+ struct kvm_memory_slot *tmp;
enum kvm_mr_change change;
+ int as_id, id;
+ int r;
r = check_memory_region_flags(mem);
if (r)
@@ -1026,52 +1024,55 @@ int __kvm_set_memory_region(struct kvm *kvm,
if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
return -EINVAL;
- slot = id_to_memslot(__kvm_memslots(kvm, as_id), id);
- base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
- npages = mem->memory_size >> PAGE_SHIFT;
-
- if (npages > KVM_MEM_MAX_NR_PAGES)
- return -EINVAL;
-
/*
* Make a full copy of the old memslot, the pointer will become stale
* when the memslots are re-sorted by update_memslots().
*/
- old = *slot;
+ tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id);
+ old = *tmp;
+ tmp = NULL;
+
if (!mem->memory_size)
return kvm_delete_memslot(kvm, mem, &old, as_id);
- new = old;
-
new.id = id;
- new.base_gfn = base_gfn;
- new.npages = npages;
+ new.base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
+ new.npages = mem->memory_size >> PAGE_SHIFT;
new.flags = mem->flags;
new.userspace_addr = mem->userspace_addr;
+ if (new.npages > KVM_MEM_MAX_NR_PAGES)
+ return -EINVAL;
+
if (!old.npages) {
change = KVM_MR_CREATE;
+ new.dirty_bitmap = NULL;
+ memset(&new.arch, 0, sizeof(new.arch));
} else { /* Modify an existing slot. */
if ((new.userspace_addr != old.userspace_addr) ||
- (npages != old.npages) ||
+ (new.npages != old.npages) ||
((new.flags ^ old.flags) & KVM_MEM_READONLY))
return -EINVAL;
- if (base_gfn != old.base_gfn)
+ if (new.base_gfn != old.base_gfn)
change = KVM_MR_MOVE;
else if (new.flags != old.flags)
change = KVM_MR_FLAGS_ONLY;
else /* Nothing to change. */
return 0;
+
+ /* Copy dirty_bitmap and arch from the current memslot. */
+ new.dirty_bitmap = old.dirty_bitmap;
+ memcpy(&new.arch, &old.arch, sizeof(new.arch));
}
if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) {
/* Check for overlaps */
- kvm_for_each_memslot(slot, __kvm_memslots(kvm, as_id)) {
- if (slot->id == id)
+ kvm_for_each_memslot(tmp, __kvm_memslots(kvm, as_id)) {
+ if (tmp->id == id)
continue;
- if (!((base_gfn + npages <= slot->base_gfn) ||
- (base_gfn >= slot->base_gfn + slot->npages)))
+ if (!((new.base_gfn + new.npages <= tmp->base_gfn) ||
+ (new.base_gfn >= tmp->base_gfn + tmp->npages)))
return -EEXIST;
}
}
--
2.22.0
next prev parent reply other threads:[~2019-09-11 18:51 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-11 18:50 [PATCH 00/13] KVM: Dynamically size memslot arrays Sean Christopherson
2019-09-11 18:50 ` [PATCH 01/13] KVM: Reinstall old memslots if arch preparation fails Sean Christopherson
2019-09-11 18:50 ` [PATCH 02/13] KVM: PPC: Move memslot memory allocation into prepare_memory_region() Sean Christopherson
2019-09-19 0:23 ` Paul Mackerras
2019-09-11 18:50 ` [PATCH 03/13] KVM: x86: Allocate memslot resources during prepare_memory_region() Sean Christopherson
2019-09-11 18:50 ` [PATCH 04/13] KVM: Drop kvm_arch_create_memslot() Sean Christopherson
2019-09-12 11:31 ` Janosch Frank
2019-09-11 18:50 ` [PATCH 05/13] KVM: Refactor error handling for setting memory region Sean Christopherson
2019-09-12 11:36 ` Janosch Frank
2019-09-11 18:50 ` [PATCH 06/13] KVM: Move setting of memslot into helper routine Sean Christopherson
2019-09-11 18:50 ` [PATCH 07/13] KVM: Move memslot deletion to helper function Sean Christopherson
2019-09-11 18:50 ` [PATCH 08/13] KVM: Simplify kvm_free_memslot() and all its descendents Sean Christopherson
2019-09-11 18:50 ` Sean Christopherson [this message]
2019-09-11 18:50 ` [PATCH 10/13] KVM: Provide common implementation for generic dirty log functions Sean Christopherson
2019-09-19 0:22 ` Paul Mackerras
2019-09-19 19:39 ` Sean Christopherson
2019-09-11 18:50 ` [PATCH 11/13] KVM: Ensure validity of memslot with respect to kvm_get_dirty_log() Sean Christopherson
2019-09-11 18:50 ` [PATCH 12/13] KVM: Terminate memslot walks via used_slots Sean Christopherson
2019-09-11 18:50 ` [PATCH 13/13] KVM: Dynamically size memslot array based on number of used slots Sean Christopherson
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