This patch includes the following:
1. Basic skeleton for the support
2. Enablement of x86 platform to use the same
Signed-off-by: Nitesh Narayan Lal <nilal@xxxxxxxxxx>
---
arch/x86/kvm/Makefile | 1 +
include/linux/gfp.h | 7 +++++++
virt/kvm/Kconfig | 4 ++++
virt/kvm/page_hinting.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 58 insertions(+)
create mode 100644 virt/kvm/page_hinting.c
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index 09d4b17..6f7c382 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -10,6 +10,7 @@ KVM := ../../../virt/kvm
kvm-y += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o \
$(KVM)/eventfd.o $(KVM)/irqchip.o $(KVM)/vfio.o
kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o
+kvm-$(CONFIG_KVM_FREE_PAGE_HINTING) += $(KVM)/page_hinting.o
kvm-y += x86.o mmu.o emulate.o i8259.o irq.o lapic.o \
i8254.o ioapic.o irq_comm.o cpuid.o pmu.o mtrr.o \
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index a89d37e..37963b8 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -424,6 +424,13 @@ static inline struct zonelist *node_zonelist(int nid, gfp_t flags)
return NODE_DATA(nid)->node_zonelists + gfp_zonelist(flags);
}
+#ifdef CONFIG_KVM_FREE_PAGE_HINTING
+#define HAVE_ARCH_ALLOC_PAGE
+#define HAVE_ARCH_FREE_PAGE
+void arch_free_page(struct page *page, int order);
+void arch_alloc_page(struct page *page, int order);
+#endif
+
#ifndef HAVE_ARCH_FREE_PAGE
static inline void arch_free_page(struct page *page, int order) { }
#endif
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index b0cc1a3..57f1c7b 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -50,3 +50,7 @@ config KVM_COMPAT
config HAVE_KVM_IRQ_BYPASS
bool
+
+config KVM_FREE_PAGE_HINTING
+ def_bool m
+ depends on KVM
diff --git a/virt/kvm/page_hinting.c b/virt/kvm/page_hinting.c
new file mode 100644
index 0000000..39d2b1d
--- /dev/null
+++ b/virt/kvm/page_hinting.c
@@ -0,0 +1,46 @@
+#include <linux/gfp.h>
+#include <linux/mm.h>
+#include <linux/page_ref.h>
+#include <linux/kvm_host.h>
+#include <linux/sort.h>
+
+#include <trace/events/kvm.h>
+
+#define MAX_FGPT_ENTRIES 1000
+#define HYPERLIST_THRESHOLD 500
+/*
+ * struct kvm_free_pages - Tracks the pages which are freed by the guest.
+ * @pfn - page frame number for the page which is to be freed
+ * @pages - number of pages which are supposed to be freed.
+ * A global array object is used to hold the list of pfn and number of pages
+ * which are freed by the guest. This list may also have fragmentated pages so
+ * defragmentation is a must prior to the hypercall.
+ */
+struct kvm_free_pages {
+ unsigned long pfn;
+ unsigned int pages;
+};
+
+/*
+ * hypervisor_pages - It is a dummy structure passed with the hypercall.
+ * @pfn - page frame number for the page which is to be freed.
+ * @pages - number of pages which are supposed to be freed.
+ * A global array object is used to to hold the list of pfn and pages and is
+ * passed as part of the hypercall.
+ */
+struct hypervisor_pages {
+ unsigned long pfn;
+ unsigned int pages;
+};
+
+DEFINE_PER_CPU(struct kvm_free_pages [MAX_FGPT_ENTRIES], kvm_pt);
+DEFINE_PER_CPU(int, kvm_pt_idx);
+struct hypervisor_pages hypervisor_pagelist[MAX_FGPT_ENTRIES];
+
+void arch_alloc_page(struct page *page, int order)
+{
+}
+
+void arch_free_page(struct page *page, int order)
+{
+}
--
2.9.4
