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Message-Id: <1207251170-5013-22-git-send-email-avi@qumranet.com>
Date: Thu, 3 Apr 2008 22:32:36 +0300
From: Avi Kivity <avi@...ranet.com>
To: kvm-devel@...ts.sourceforge.net
Cc: linux-kernel@...r.kernel.org, Marcelo Tosatti <mtosatti@...hat.com>
Subject: [PATCH 21/35] KVM: MMU: hypercall based pte updates and TLB flushes
From: Marcelo Tosatti <mtosatti@...hat.com>
Hypercall based pte updates are faster than faults, and also allow use
of the lazy MMU mode to batch operations.
Don't report the feature if two dimensional paging is enabled.
[avi:
- one mmu_op hypercall instead of one per op
- allow 64-bit gpa on hypercall
- don't pass host errors (-ENOMEM) to guest]
[akpm: warning fix on i386]
Signed-off-by: Marcelo Tosatti <mtosatti@...hat.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Avi Kivity <avi@...ranet.com>
---
arch/x86/kvm/mmu.c | 136 +++++++++++++++++++++++++++++++++++++++++++-
arch/x86/kvm/x86.c | 18 ++++++-
include/asm-x86/kvm_host.h | 4 +
include/asm-x86/kvm_para.h | 29 +++++++++
include/linux/kvm.h | 1 +
include/linux/kvm_para.h | 5 +-
6 files changed, 190 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 414405b..072e942 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -28,6 +28,7 @@
#include <linux/module.h>
#include <linux/swap.h>
#include <linux/hugetlb.h>
+#include <linux/compiler.h>
#include <asm/page.h>
#include <asm/cmpxchg.h>
@@ -40,7 +41,7 @@
* 2. while doing 1. it walks guest-physical to host-physical
* If the hardware supports that we don't need to do shadow paging.
*/
-static bool tdp_enabled = false;
+bool tdp_enabled = false;
#undef MMU_DEBUG
@@ -167,6 +168,13 @@ static int dbg = 1;
#define ACC_USER_MASK PT_USER_MASK
#define ACC_ALL (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)
+struct kvm_pv_mmu_op_buffer {
+ void *ptr;
+ unsigned len;
+ unsigned processed;
+ char buf[512] __aligned(sizeof(long));
+};
+
struct kvm_rmap_desc {
u64 *shadow_ptes[RMAP_EXT];
struct kvm_rmap_desc *more;
@@ -2003,6 +2011,132 @@ unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
return nr_mmu_pages;
}
+static void *pv_mmu_peek_buffer(struct kvm_pv_mmu_op_buffer *buffer,
+ unsigned len)
+{
+ if (len > buffer->len)
+ return NULL;
+ return buffer->ptr;
+}
+
+static void *pv_mmu_read_buffer(struct kvm_pv_mmu_op_buffer *buffer,
+ unsigned len)
+{
+ void *ret;
+
+ ret = pv_mmu_peek_buffer(buffer, len);
+ if (!ret)
+ return ret;
+ buffer->ptr += len;
+ buffer->len -= len;
+ buffer->processed += len;
+ return ret;
+}
+
+static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
+ gpa_t addr, gpa_t value)
+{
+ int bytes = 8;
+ int r;
+
+ if (!is_long_mode(vcpu) && !is_pae(vcpu))
+ bytes = 4;
+
+ r = mmu_topup_memory_caches(vcpu);
+ if (r)
+ return r;
+
+ if (!__emulator_write_phys(vcpu, addr, &value, bytes))
+ return -EFAULT;
+
+ return 1;
+}
+
+static int kvm_pv_mmu_flush_tlb(struct kvm_vcpu *vcpu)
+{
+ kvm_x86_ops->tlb_flush(vcpu);
+ return 1;
+}
+
+static int kvm_pv_mmu_release_pt(struct kvm_vcpu *vcpu, gpa_t addr)
+{
+ spin_lock(&vcpu->kvm->mmu_lock);
+ mmu_unshadow(vcpu->kvm, addr >> PAGE_SHIFT);
+ spin_unlock(&vcpu->kvm->mmu_lock);
+ return 1;
+}
+
+static int kvm_pv_mmu_op_one(struct kvm_vcpu *vcpu,
+ struct kvm_pv_mmu_op_buffer *buffer)
+{
+ struct kvm_mmu_op_header *header;
+
+ header = pv_mmu_peek_buffer(buffer, sizeof *header);
+ if (!header)
+ return 0;
+ switch (header->op) {
+ case KVM_MMU_OP_WRITE_PTE: {
+ struct kvm_mmu_op_write_pte *wpte;
+
+ wpte = pv_mmu_read_buffer(buffer, sizeof *wpte);
+ if (!wpte)
+ return 0;
+ return kvm_pv_mmu_write(vcpu, wpte->pte_phys,
+ wpte->pte_val);
+ }
+ case KVM_MMU_OP_FLUSH_TLB: {
+ struct kvm_mmu_op_flush_tlb *ftlb;
+
+ ftlb = pv_mmu_read_buffer(buffer, sizeof *ftlb);
+ if (!ftlb)
+ return 0;
+ return kvm_pv_mmu_flush_tlb(vcpu);
+ }
+ case KVM_MMU_OP_RELEASE_PT: {
+ struct kvm_mmu_op_release_pt *rpt;
+
+ rpt = pv_mmu_read_buffer(buffer, sizeof *rpt);
+ if (!rpt)
+ return 0;
+ return kvm_pv_mmu_release_pt(vcpu, rpt->pt_phys);
+ }
+ default: return 0;
+ }
+}
+
+int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
+ gpa_t addr, unsigned long *ret)
+{
+ int r;
+ struct kvm_pv_mmu_op_buffer buffer;
+
+ down_read(&vcpu->kvm->slots_lock);
+ down_read(¤t->mm->mmap_sem);
+
+ buffer.ptr = buffer.buf;
+ buffer.len = min_t(unsigned long, bytes, sizeof buffer.buf);
+ buffer.processed = 0;
+
+ r = kvm_read_guest(vcpu->kvm, addr, buffer.buf, buffer.len);
+ if (r)
+ goto out;
+
+ while (buffer.len) {
+ r = kvm_pv_mmu_op_one(vcpu, &buffer);
+ if (r < 0)
+ goto out;
+ if (r == 0)
+ break;
+ }
+
+ r = 1;
+out:
+ *ret = buffer.processed;
+ up_read(¤t->mm->mmap_sem);
+ up_read(&vcpu->kvm->slots_lock);
+ return r;
+}
+
#ifdef AUDIT
static const char *audit_msg;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 03ba402..63afca1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -832,6 +832,9 @@ int kvm_dev_ioctl_check_extension(long ext)
case KVM_CAP_NR_MEMSLOTS:
r = KVM_MEMORY_SLOTS;
break;
+ case KVM_CAP_PV_MMU:
+ r = !tdp_enabled;
+ break;
default:
r = 0;
break;
@@ -2452,9 +2455,19 @@ int kvm_emulate_halt(struct kvm_vcpu *vcpu)
}
EXPORT_SYMBOL_GPL(kvm_emulate_halt);
+static inline gpa_t hc_gpa(struct kvm_vcpu *vcpu, unsigned long a0,
+ unsigned long a1)
+{
+ if (is_long_mode(vcpu))
+ return a0;
+ else
+ return a0 | ((gpa_t)a1 << 32);
+}
+
int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
{
unsigned long nr, a0, a1, a2, a3, ret;
+ int r = 1;
kvm_x86_ops->cache_regs(vcpu);
@@ -2476,6 +2489,9 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
case KVM_HC_VAPIC_POLL_IRQ:
ret = 0;
break;
+ case KVM_HC_MMU_OP:
+ r = kvm_pv_mmu_op(vcpu, a0, hc_gpa(vcpu, a1, a2), &ret);
+ break;
default:
ret = -KVM_ENOSYS;
break;
@@ -2483,7 +2499,7 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
vcpu->arch.regs[VCPU_REGS_RAX] = ret;
kvm_x86_ops->decache_regs(vcpu);
++vcpu->stat.hypercalls;
- return 0;
+ return r;
}
EXPORT_SYMBOL_GPL(kvm_emulate_hypercall);
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index c8e51f8..52e276c 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -433,6 +433,10 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3);
int __emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
const void *val, int bytes);
+int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
+ gpa_t addr, unsigned long *ret);
+
+extern bool tdp_enabled;
enum emulation_result {
EMULATE_DONE, /* no further processing */
diff --git a/include/asm-x86/kvm_para.h b/include/asm-x86/kvm_para.h
index ed5df3a..5098459 100644
--- a/include/asm-x86/kvm_para.h
+++ b/include/asm-x86/kvm_para.h
@@ -12,10 +12,39 @@
#define KVM_CPUID_FEATURES 0x40000001
#define KVM_FEATURE_CLOCKSOURCE 0
#define KVM_FEATURE_NOP_IO_DELAY 1
+#define KVM_FEATURE_MMU_OP 2
#define MSR_KVM_WALL_CLOCK 0x11
#define MSR_KVM_SYSTEM_TIME 0x12
+#define KVM_MAX_MMU_OP_BATCH 32
+
+/* Operations for KVM_HC_MMU_OP */
+#define KVM_MMU_OP_WRITE_PTE 1
+#define KVM_MMU_OP_FLUSH_TLB 2
+#define KVM_MMU_OP_RELEASE_PT 3
+
+/* Payload for KVM_HC_MMU_OP */
+struct kvm_mmu_op_header {
+ __u32 op;
+ __u32 pad;
+};
+
+struct kvm_mmu_op_write_pte {
+ struct kvm_mmu_op_header header;
+ __u64 pte_phys;
+ __u64 pte_val;
+};
+
+struct kvm_mmu_op_flush_tlb {
+ struct kvm_mmu_op_header header;
+};
+
+struct kvm_mmu_op_release_pt {
+ struct kvm_mmu_op_header header;
+ __u64 pt_phys;
+};
+
#ifdef __KERNEL__
#include <asm/processor.h>
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 76f0947..c1b502a 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -238,6 +238,7 @@ struct kvm_vapic_addr {
#define KVM_CAP_NR_MEMSLOTS 10 /* returns max memory slots per vm */
#define KVM_CAP_PIT 11
#define KVM_CAP_NOP_IO_DELAY 12
+#define KVM_CAP_PV_MMU 13
/*
* ioctls for VM fds
diff --git a/include/linux/kvm_para.h b/include/linux/kvm_para.h
index 9c462c9..3ddce03 100644
--- a/include/linux/kvm_para.h
+++ b/include/linux/kvm_para.h
@@ -11,8 +11,11 @@
/* Return values for hypercalls */
#define KVM_ENOSYS 1000
+#define KVM_EFAULT EFAULT
+#define KVM_E2BIG E2BIG
-#define KVM_HC_VAPIC_POLL_IRQ 1
+#define KVM_HC_VAPIC_POLL_IRQ 1
+#define KVM_HC_MMU_OP 2
/*
* hypercalls use architecture specific
--
1.5.4.5
--
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