[PATCH v6 07/11] KVM: Introduce kvm_write_guest_offset_cached
From: Pan Xinhui <hidden>
Date: 2016-10-28 04:27:13
Also in:
kvm, linux-s390, linuxppc-dev
Subsystem:
kernel virtual machine (kvm), the rest · Maintainers:
Paolo Bonzini, Linus Torvalds
It allows us to update some status or field of one struct partially. We can also save one kvm_read_guest_cached if we just update one filed of the struct regardless of its current value. Signed-off-by: Pan Xinhui <redacted> --- include/linux/kvm_host.h | 2 ++ virt/kvm/kvm_main.c | 20 ++++++++++++++------ 2 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 01c0b9c..6f00237 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h@@ -645,6 +645,8 @@ int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data, unsigned long len); int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, void *data, unsigned long len); +int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, int offset, unsigned long len); int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, gpa_t gpa, unsigned long len); int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2907b7b..95308ee 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c@@ -1972,30 +1972,38 @@ int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, } EXPORT_SYMBOL_GPL(kvm_gfn_to_hva_cache_init); -int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, - void *data, unsigned long len) +int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, int offset, unsigned long len) { struct kvm_memslots *slots = kvm_memslots(kvm); int r; + gpa_t gpa = ghc->gpa + offset; - BUG_ON(len > ghc->len); + BUG_ON(len + offset > ghc->len); if (slots->generation != ghc->generation) kvm_gfn_to_hva_cache_init(kvm, ghc, ghc->gpa, ghc->len); if (unlikely(!ghc->memslot)) - return kvm_write_guest(kvm, ghc->gpa, data, len); + return kvm_write_guest(kvm, gpa, data, len); if (kvm_is_error_hva(ghc->hva)) return -EFAULT; - r = __copy_to_user((void __user *)ghc->hva, data, len); + r = __copy_to_user((void __user *)ghc->hva + offset, data, len); if (r) return -EFAULT; - mark_page_dirty_in_slot(ghc->memslot, ghc->gpa >> PAGE_SHIFT); + mark_page_dirty_in_slot(ghc->memslot, gpa >> PAGE_SHIFT); return 0; } +EXPORT_SYMBOL_GPL(kvm_write_guest_offset_cached); + +int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc, + void *data, unsigned long len) +{ + return kvm_write_guest_offset_cached(kvm, ghc, data, 0, len); +} EXPORT_SYMBOL_GPL(kvm_write_guest_cached); int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
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2.4.11