[PATCH 18/45] KVM: MMU: unify slots_lock usage
From: Avi Kivity
Date: Thu Apr 17 2008 - 05:19:38 EST
From: Marcelo Tosatti <marcelo@xxxxxxxxx>
Unify slots_lock acquision around vcpu_run(). This is simpler and less
error-prone.
Also fix some callsites that were not grabbing the lock properly.
[avi: drop slots_lock while in guest mode to avoid holding the lock
for indefinite periods]
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 13 +---------
arch/x86/kvm/paging_tmpl.h | 4 ---
arch/x86/kvm/vmx.c | 6 ++--
arch/x86/kvm/x86.c | 53 ++++++++++++++++---------------------------
include/asm-x86/kvm_host.h | 2 +-
5 files changed, 26 insertions(+), 52 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 6fc3421..c563283 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1204,8 +1204,6 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
struct page *page;
- down_read(&vcpu->kvm->slots_lock);
-
down_read(¤t->mm->mmap_sem);
if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
gfn &= ~(KVM_PAGES_PER_HPAGE-1);
@@ -1218,7 +1216,6 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
/* mmio */
if (is_error_page(page)) {
kvm_release_page_clean(page);
- up_read(&vcpu->kvm->slots_lock);
return 1;
}
@@ -1228,7 +1225,6 @@ static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
PT32E_ROOT_LEVEL);
spin_unlock(&vcpu->kvm->mmu_lock);
- up_read(&vcpu->kvm->slots_lock);
return r;
}
@@ -1376,9 +1372,9 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
largepage = 1;
}
page = gfn_to_page(vcpu->kvm, gfn);
+ up_read(¤t->mm->mmap_sem);
if (is_error_page(page)) {
kvm_release_page_clean(page);
- up_read(¤t->mm->mmap_sem);
return 1;
}
spin_lock(&vcpu->kvm->mmu_lock);
@@ -1386,7 +1382,6 @@ static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
largepage, gfn, page, TDP_ROOT_LEVEL);
spin_unlock(&vcpu->kvm->mmu_lock);
- up_read(¤t->mm->mmap_sem);
return r;
}
@@ -1808,9 +1803,7 @@ int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
gpa_t gpa;
int r;
- down_read(&vcpu->kvm->slots_lock);
gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
- up_read(&vcpu->kvm->slots_lock);
spin_lock(&vcpu->kvm->mmu_lock);
r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
@@ -2063,7 +2056,7 @@ static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
if (r)
return r;
- if (!__emulator_write_phys(vcpu, addr, &value, bytes))
+ if (!emulator_write_phys(vcpu, addr, &value, bytes))
return -EFAULT;
return 1;
@@ -2127,7 +2120,6 @@ int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
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;
@@ -2150,7 +2142,6 @@ int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
out:
*ret = buffer.processed;
up_read(¤t->mm->mmap_sem);
- up_read(&vcpu->kvm->slots_lock);
return r;
}
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index e9ae5db..57d872a 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -388,7 +388,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
if (r)
return r;
- down_read(&vcpu->kvm->slots_lock);
/*
* Look up the shadow pte for the faulting address.
*/
@@ -402,7 +401,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
pgprintk("%s: guest page fault\n", __func__);
inject_page_fault(vcpu, addr, walker.error_code);
vcpu->arch.last_pt_write_count = 0; /* reset fork detector */
- up_read(&vcpu->kvm->slots_lock);
return 0;
}
@@ -422,7 +420,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
if (is_error_page(page)) {
pgprintk("gfn %x is mmio\n", walker.gfn);
kvm_release_page_clean(page);
- up_read(&vcpu->kvm->slots_lock);
return 1;
}
@@ -440,7 +437,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
++vcpu->stat.pf_fixed;
kvm_mmu_audit(vcpu, "post page fault (fixed)");
spin_unlock(&vcpu->kvm->mmu_lock);
- up_read(&vcpu->kvm->slots_lock);
return write_pt;
}
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 87eee7a..6249810 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1505,7 +1505,6 @@ static int init_rmode_tss(struct kvm *kvm)
int ret = 0;
int r;
- down_read(&kvm->slots_lock);
r = kvm_clear_guest_page(kvm, fn, 0, PAGE_SIZE);
if (r < 0)
goto out;
@@ -1528,7 +1527,6 @@ static int init_rmode_tss(struct kvm *kvm)
ret = 1;
out:
- up_read(&kvm->slots_lock);
return ret;
}
@@ -1730,6 +1728,7 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
u64 msr;
int ret;
+ down_read(&vcpu->kvm->slots_lock);
if (!init_rmode_tss(vmx->vcpu.kvm)) {
ret = -ENOMEM;
goto out;
@@ -1833,9 +1832,10 @@ static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
vpid_sync_vcpu_all(vmx);
- return 0;
+ ret = 0;
out:
+ up_read(&vcpu->kvm->slots_lock);
return ret;
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 32d9100..e6a38bf 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -201,7 +201,6 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
int ret;
u64 pdpte[ARRAY_SIZE(vcpu->arch.pdptrs)];
- down_read(&vcpu->kvm->slots_lock);
ret = kvm_read_guest_page(vcpu->kvm, pdpt_gfn, pdpte,
offset * sizeof(u64), sizeof(pdpte));
if (ret < 0) {
@@ -218,7 +217,6 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
memcpy(vcpu->arch.pdptrs, pdpte, sizeof(vcpu->arch.pdptrs));
out:
- up_read(&vcpu->kvm->slots_lock);
return ret;
}
@@ -233,13 +231,11 @@ static bool pdptrs_changed(struct kvm_vcpu *vcpu)
if (is_long_mode(vcpu) || !is_pae(vcpu))
return false;
- down_read(&vcpu->kvm->slots_lock);
r = kvm_read_guest(vcpu->kvm, vcpu->arch.cr3 & ~31u, pdpte, sizeof(pdpte));
if (r < 0)
goto out;
changed = memcmp(pdpte, vcpu->arch.pdptrs, sizeof(pdpte)) != 0;
out:
- up_read(&vcpu->kvm->slots_lock);
return changed;
}
@@ -377,7 +373,6 @@ void kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
*/
}
- down_read(&vcpu->kvm->slots_lock);
/*
* Does the new cr3 value map to physical memory? (Note, we
* catch an invalid cr3 even in real-mode, because it would
@@ -393,7 +388,6 @@ void kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
vcpu->arch.cr3 = cr3;
vcpu->arch.mmu.new_cr3(vcpu);
}
- up_read(&vcpu->kvm->slots_lock);
}
EXPORT_SYMBOL_GPL(kvm_set_cr3);
@@ -503,7 +497,6 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
version++;
- down_read(&kvm->slots_lock);
kvm_write_guest(kvm, wall_clock, &version, sizeof(version));
wc_ts = current_kernel_time();
@@ -515,7 +508,6 @@ static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
version++;
kvm_write_guest(kvm, wall_clock, &version, sizeof(version));
- up_read(&kvm->slots_lock);
}
static void kvm_write_guest_time(struct kvm_vcpu *v)
@@ -609,10 +601,8 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
vcpu->arch.hv_clock.tsc_shift = 22;
down_read(¤t->mm->mmap_sem);
- down_read(&vcpu->kvm->slots_lock);
vcpu->arch.time_page =
gfn_to_page(vcpu->kvm, data >> PAGE_SHIFT);
- up_read(&vcpu->kvm->slots_lock);
up_read(¤t->mm->mmap_sem);
if (is_error_page(vcpu->arch.time_page)) {
@@ -715,9 +705,11 @@ static int __msr_io(struct kvm_vcpu *vcpu, struct kvm_msrs *msrs,
vcpu_load(vcpu);
+ down_read(&vcpu->kvm->slots_lock);
for (i = 0; i < msrs->nmsrs; ++i)
if (do_msr(vcpu, entries[i].index, &entries[i].data))
break;
+ up_read(&vcpu->kvm->slots_lock);
vcpu_put(vcpu);
@@ -1768,7 +1760,6 @@ int emulator_read_std(unsigned long addr,
void *data = val;
int r = X86EMUL_CONTINUE;
- down_read(&vcpu->kvm->slots_lock);
while (bytes) {
gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
unsigned offset = addr & (PAGE_SIZE-1);
@@ -1790,7 +1781,6 @@ int emulator_read_std(unsigned long addr,
addr += tocopy;
}
out:
- up_read(&vcpu->kvm->slots_lock);
return r;
}
EXPORT_SYMBOL_GPL(emulator_read_std);
@@ -1809,9 +1799,7 @@ static int emulator_read_emulated(unsigned long addr,
return X86EMUL_CONTINUE;
}
- down_read(&vcpu->kvm->slots_lock);
gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
- up_read(&vcpu->kvm->slots_lock);
/* For APIC access vmexit */
if ((gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
@@ -1844,7 +1832,7 @@ mmio:
return X86EMUL_UNHANDLEABLE;
}
-int __emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
+int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
const void *val, int bytes)
{
int ret;
@@ -1856,17 +1844,6 @@ int __emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
return 1;
}
-static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
- const void *val, int bytes)
-{
- int ret;
-
- down_read(&vcpu->kvm->slots_lock);
- ret =__emulator_write_phys(vcpu, gpa, val, bytes);
- up_read(&vcpu->kvm->slots_lock);
- return ret;
-}
-
static int emulator_write_emulated_onepage(unsigned long addr,
const void *val,
unsigned int bytes,
@@ -1875,9 +1852,7 @@ static int emulator_write_emulated_onepage(unsigned long addr,
struct kvm_io_device *mmio_dev;
gpa_t gpa;
- down_read(&vcpu->kvm->slots_lock);
gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
- up_read(&vcpu->kvm->slots_lock);
if (gpa == UNMAPPED_GVA) {
kvm_inject_page_fault(vcpu, addr, 2);
@@ -1954,7 +1929,6 @@ static int emulator_cmpxchg_emulated(unsigned long addr,
char *kaddr;
u64 val;
- down_read(&vcpu->kvm->slots_lock);
gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, addr);
if (gpa == UNMAPPED_GVA ||
@@ -1974,9 +1948,8 @@ static int emulator_cmpxchg_emulated(unsigned long addr,
set_64bit((u64 *)(kaddr + offset_in_page(gpa)), val);
kunmap_atomic(kaddr, KM_USER0);
kvm_release_page_dirty(page);
- emul_write:
- up_read(&vcpu->kvm->slots_lock);
}
+emul_write:
#endif
return emulator_write_emulated(addr, new, bytes, vcpu);
@@ -2368,10 +2341,8 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in,
kvm_x86_ops->skip_emulated_instruction(vcpu);
for (i = 0; i < nr_pages; ++i) {
- down_read(&vcpu->kvm->slots_lock);
page = gva_to_page(vcpu, address + i * PAGE_SIZE);
vcpu->arch.pio.guest_pages[i] = page;
- up_read(&vcpu->kvm->slots_lock);
if (!page) {
kvm_inject_gp(vcpu, 0);
free_pio_guest_pages(vcpu);
@@ -2445,7 +2416,9 @@ int kvm_emulate_halt(struct kvm_vcpu *vcpu)
++vcpu->stat.halt_exits;
if (irqchip_in_kernel(vcpu->kvm)) {
vcpu->arch.mp_state = VCPU_MP_STATE_HALTED;
+ up_read(&vcpu->kvm->slots_lock);
kvm_vcpu_block(vcpu);
+ down_read(&vcpu->kvm->slots_lock);
if (vcpu->arch.mp_state != VCPU_MP_STATE_RUNNABLE)
return -EINTR;
return 1;
@@ -2738,6 +2711,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
vcpu->arch.mp_state = VCPU_MP_STATE_RUNNABLE;
}
+ down_read(&vcpu->kvm->slots_lock);
vapic_enter(vcpu);
preempted:
@@ -2811,6 +2785,8 @@ again:
kvm_lapic_sync_to_vapic(vcpu);
+ up_read(&vcpu->kvm->slots_lock);
+
vcpu->guest_mode = 1;
kvm_guest_enter();
@@ -2837,6 +2813,8 @@ again:
preempt_enable();
+ down_read(&vcpu->kvm->slots_lock);
+
/*
* Profile KVM exit RIPs:
*/
@@ -2864,14 +2842,18 @@ again:
}
out:
+ up_read(&vcpu->kvm->slots_lock);
if (r > 0) {
kvm_resched(vcpu);
+ down_read(&vcpu->kvm->slots_lock);
goto preempted;
}
post_kvm_run_save(vcpu, kvm_run);
+ down_read(&vcpu->kvm->slots_lock);
vapic_exit(vcpu);
+ up_read(&vcpu->kvm->slots_lock);
return r;
}
@@ -2906,9 +2888,12 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
memcpy(vcpu->mmio_data, kvm_run->mmio.data, 8);
vcpu->mmio_read_completed = 1;
vcpu->mmio_needed = 0;
+
+ down_read(&vcpu->kvm->slots_lock);
r = emulate_instruction(vcpu, kvm_run,
vcpu->arch.mmio_fault_cr2, 0,
EMULTYPE_NO_DECODE);
+ up_read(&vcpu->kvm->slots_lock);
if (r == EMULATE_DO_MMIO) {
/*
* Read-modify-write. Back to userspace.
@@ -3817,7 +3802,9 @@ fail:
void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
{
kvm_free_lapic(vcpu);
+ down_read(&vcpu->kvm->slots_lock);
kvm_mmu_destroy(vcpu);
+ up_read(&vcpu->kvm->slots_lock);
free_page((unsigned long)vcpu->arch.pio_data);
}
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index 4382ca0..e6d8df6 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -445,7 +445,7 @@ void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages);
int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3);
-int __emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
+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);
--
1.5.5
--
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