[PATCH v13 44/85] KVM: x86/mmu: Convert page fault paths to kvm_faultin_pfn()

Sean Christopherson
2024-10-10T18:26:24Z

Convert KVM x86 to use the recently introduced __kvm_faultin_pfn().
Opportunstically capture the refcounted_page grabbed by KVM for use in
future changes.

No functional change intended.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/mmu/mmu.c | 14 ++++++++++----
arch/x86/kvm/mmu/mmu_internal.h | 1 +
2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index f730870887dd..2e2076287aaf 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4416,11 +4416,14 @@ static int kvm_mmu_faultin_pfn_private(struct kvm_vcpu *vcpu,
static int __kvm_mmu_faultin_pfn(struct kvm_vcpu *vcpu,
struct kvm_page_fault *fault)
{
+ unsigned int foll = fault->write ? FOLL_WRITE : 0;
+
if (fault->is_private)
return kvm_mmu_faultin_pfn_private(vcpu, fault);

- fault->pfn = __gfn_to_pfn_memslot(fault->slot, fault->gfn, false, true,
- fault->write, &fault->map_writable);
+ foll |= FOLL_NOWAIT;
+ fault->pfn = __kvm_faultin_pfn(fault->slot, fault->gfn, foll,
+ &fault->map_writable, &fault->refcounted_page);

/*
* If resolving the page failed because I/O is needed to fault-in the
@@ -4447,8 +4450,11 @@ static int __kvm_mmu_faultin_pfn(struct kvm_vcpu *vcpu,
* to wait for IO. Note, gup always bails if it is unable to quickly
* get a page and a fatal signal, i.e. SIGKILL, is pending.
*/
- fault->pfn = __gfn_to_pfn_memslot(fault->slot, fault->gfn, true, true,
- fault->write, &fault->map_writable);
+ foll |= FOLL_INTERRUPTIBLE;
+ foll &= ~FOLL_NOWAIT;
+ fault->pfn = __kvm_faultin_pfn(fault->slot, fault->gfn, foll,
+ &fault->map_writable, &fault->refcounted_page);
+
return RET_PF_CONTINUE;
}

diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 59e600f6ff9d..fabbea504a69 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -238,6 +238,7 @@ struct kvm_page_fault {
/* Outputs of kvm_mmu_faultin_pfn(). */
unsigned long mmu_seq;
kvm_pfn_t pfn;
+ struct page *refcounted_page;
bool map_writable;

/*
--
2.47.0.rc1.288.g06298d1525-goog