[PATCH v4 3/5] KVM: x86: hyperv: use get_vcpu_by_vpidx() in kvm_hv_flush_tlb()

2018-07-03 Thread Vitaly Kuznetsov
VP_INDEX almost always matches VCPU id and get_vcpu_by_vpidx() is fast,
use it instead of traversing full vCPU list every time.

To support the change split off get_vcpu_idx_by_vpidx() from
get_vcpu_by_vpidx().

Signed-off-by: Vitaly Kuznetsov 
---
 arch/x86/kvm/hyperv.c | 78 ---
 1 file changed, 31 insertions(+), 47 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index c5b921c0a467..8db20c9d4529 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -127,20 +127,31 @@ static int synic_set_sint(struct kvm_vcpu_hv_synic 
*synic, int sint,
return 0;
 }
 
-static struct kvm_vcpu *get_vcpu_by_vpidx(struct kvm *kvm, u32 vpidx)
+static u32 get_vcpu_idx_by_vpidx(struct kvm *kvm, u32 vpidx)
 {
struct kvm_vcpu *vcpu = NULL;
int i;
 
if (vpidx >= KVM_MAX_VCPUS)
-   return NULL;
+   return U32_MAX;
 
vcpu = kvm_get_vcpu(kvm, vpidx);
if (vcpu && vcpu_to_hv_vcpu(vcpu)->vp_index == vpidx)
-   return vcpu;
+   return vpidx;
kvm_for_each_vcpu(i, vcpu, kvm)
if (vcpu_to_hv_vcpu(vcpu)->vp_index == vpidx)
-   return vcpu;
+   return i;
+   return U32_MAX;
+}
+
+static __always_inline struct kvm_vcpu *get_vcpu_by_vpidx(struct kvm *kvm,
+ u32 vpidx)
+{
+   u32 vcpu_idx = get_vcpu_idx_by_vpidx(kvm, vpidx);
+
+   if (vcpu_idx < KVM_MAX_VCPUS)
+   return kvm_get_vcpu(kvm, vcpu_idx);
+
return NULL;
 }
 
@@ -1244,20 +1255,6 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 
msr, u64 *pdata)
return kvm_hv_get_msr(vcpu, msr, pdata);
 }
 
-static __always_inline int get_sparse_bank_no(u64 valid_bank_mask, int bank_no)
-{
-   int i = 0, j;
-
-   if (!(valid_bank_mask & BIT_ULL(bank_no)))
-   return -1;
-
-   for (j = 0; j < bank_no; j++)
-   if (valid_bank_mask & BIT_ULL(j))
-   i++;
-
-   return i;
-}
-
 static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa,
u16 rep_cnt, bool ex)
 {
@@ -1265,11 +1262,10 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu 
*current_vcpu, u64 ingpa,
struct kvm_vcpu_hv *hv_current = ¤t_vcpu->arch.hyperv;
struct hv_tlb_flush_ex flush_ex;
struct hv_tlb_flush flush;
-   struct kvm_vcpu *vcpu;
unsigned long vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)] = {0};
-   unsigned long valid_bank_mask = 0;
+   unsigned long valid_bank_mask;
u64 sparse_banks[64];
-   int sparse_banks_len, i;
+   int sparse_banks_len, bank, i;
bool all_cpus;
 
if (!ex) {
@@ -1279,6 +1275,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu 
*current_vcpu, u64 ingpa,
trace_kvm_hv_flush_tlb(flush.processor_mask,
   flush.address_space, flush.flags);
 
+   valid_bank_mask = BIT_ULL(0);
sparse_banks[0] = flush.processor_mask;
all_cpus = flush.flags & HV_FLUSH_ALL_PROCESSORS;
} else {
@@ -1319,38 +1316,25 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu 
*current_vcpu, u64 ingpa,
goto ret_success;
}
 
-   kvm_for_each_vcpu(i, vcpu, kvm) {
-   struct kvm_vcpu_hv *hv = &vcpu->arch.hyperv;
-   int bank = hv->vp_index / 64, sbank = 0;
+   for_each_set_bit(bank, (unsigned long *)&valid_bank_mask,
+BITS_PER_LONG) {
 
-   /* Banks >64 can't be represented */
-   if (bank >= 64)
-   continue;
+   for_each_set_bit(i, (unsigned long *)&sparse_banks[bank],
+BITS_PER_LONG) {
+   u32 vp_index = bank * 64 + i;
+   u32 vcpu_idx = get_vcpu_idx_by_vpidx(kvm, vp_index);
 
-   /* Non-ex hypercalls can only address first 64 vCPUs */
-   if (!ex && bank)
-   continue;
+   /* A non-existent vCPU was specified */
+   if (vcpu_idx >= KVM_MAX_VCPUS)
+   return HV_STATUS_INVALID_HYPERCALL_INPUT;
 
-   if (ex) {
/*
-* Check is the bank of this vCPU is in sparse
-* set and get the sparse bank number.
+* vcpu->arch.cr3 may not be up-to-date for running
+* vCPUs so we can't analyze it here, flush TLB
+* regardless of the specified address space.
 */
-   sbank = get_sparse_bank_no(valid_bank_mask, bank);
-
-   if (sbank < 0)
-   continue;
+   __set_bit(vcpu_idx, vcpu_bitmap);
 

Re: [PATCH v4 3/5] KVM: x86: hyperv: use get_vcpu_by_vpidx() in kvm_hv_flush_tlb()

2018-07-09 Thread Roman Kagan
On Tue, Jul 03, 2018 at 03:42:04PM +0200, Vitaly Kuznetsov wrote:
> VP_INDEX almost always matches VCPU id and get_vcpu_by_vpidx() is fast,
> use it instead of traversing full vCPU list every time.
> 
> To support the change split off get_vcpu_idx_by_vpidx() from
> get_vcpu_by_vpidx().
> 
> Signed-off-by: Vitaly Kuznetsov 
> ---
>  arch/x86/kvm/hyperv.c | 78 
> ---
>  1 file changed, 31 insertions(+), 47 deletions(-)

Reviewed-by: Roman Kagan