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Message-ID: <573201AB.2050006@redhat.com>
Date: Tue, 10 May 2016 17:43:39 +0200
From: Paolo Bonzini <pbonzini@...hat.com>
To: Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>,
rkrcmar@...hat.com, joro@...tes.org, bp@...en8.de, gleb@...nel.org,
alex.williamson@...hat.com
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, wei@...hat.com,
sherry.hurwitz@....com
Subject: Re: [PART1 V5 13/13] svm: Manage vcpu load/unload when enable AVIC
On 04/05/2016 21:09, Suravee Suthikulpanit wrote:
> From: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
>
> When a vcpu is loaded/unloaded to a physical core, we need to update
> host physical APIC ID information in the Physical APIC-ID table
> accordingly.
>
> Also, when vCPU is blocking/un-blocking (due to halt instruction),
> we need to make sure that the is-running bit in set accordingly in the
> physical APIC-ID table.
>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
> Reviewed-by: Radim Krčmář <rkrcmar@...hat.com>
> ---
I think this is the only patch that needs a little more work, because
there are a bunch of unused return values that really should be
WARN_ON. In addition the load and put cases are different enough that
they should be separate functions.
Can you please test this?
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f3dbf1d33a61..3168d6c8d24f 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -184,7 +184,7 @@ struct vcpu_svm {
u32 ldr_reg;
struct page *avic_backing_page;
u64 *avic_physical_id_cache;
- bool avic_is_blocking;
+ bool avic_is_running;
};
#define AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK (0xFF)
@@ -1321,18 +1321,20 @@ free_avic:
/**
* This function is called during VCPU halt/unhalt.
*/
-static int avic_set_running(struct kvm_vcpu *vcpu, bool is_run)
+static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run)
{
u64 entry;
int h_physical_id = __default_cpu_present_to_apicid(vcpu->cpu);
struct vcpu_svm *svm = to_svm(vcpu);
if (!kvm_vcpu_apicv_active(vcpu))
- return 0;
+ return;
+
+ svm->avic_is_running = is_run;
/* ID = 0xff (broadcast), ID > 0xff (reserved) */
- if (h_physical_id >= AVIC_MAX_PHYSICAL_ID_COUNT)
- return -EINVAL;
+ if (WARN_ON(h_physical_id >= AVIC_MAX_PHYSICAL_ID_COUNT))
+ return;
entry = READ_ONCE(*(svm->avic_physical_id_cache));
WARN_ON(is_run == !!(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK));
@@ -1341,36 +1343,45 @@ static int avic_set_running(struct kvm_vcpu *vcpu, bool is_run)
if (is_run)
entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
-
- return 0;
}
-static int avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu, bool is_load)
+static void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
u64 entry;
+ /* ID = 0xff (broadcast), ID > 0xff (reserved) */
int h_physical_id = __default_cpu_present_to_apicid(cpu);
struct vcpu_svm *svm = to_svm(vcpu);
if (!kvm_vcpu_apicv_active(vcpu))
- return 0;
+ return;
- /* ID = 0xff (broadcast), ID > 0xff (reserved) */
- if (h_physical_id >= AVIC_MAX_PHYSICAL_ID_COUNT)
- return -EINVAL;
+ if (WARN_ON(h_physical_id >= AVIC_MAX_PHYSICAL_ID_COUNT))
+ return;
entry = READ_ONCE(*(svm->avic_physical_id_cache));
- WARN_ON(is_load && (entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK));
+ WARN_ON(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK);
+
+ entry &= ~AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK;
+ entry |= (h_physical_id & AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK);
entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
- if (is_load) {
- entry &= ~AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK;
- entry |= (h_physical_id & AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK);
- if (!svm->avic_is_blocking)
- entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
- }
+ if (svm->avic_is_running)
+ entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
+
WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+}
- return 0;
+static void avic_vcpu_put(struct kvm_vcpu *vcpu)
+{
+ u64 entry;
+ struct vcpu_svm *svm = to_svm(vcpu);
+
+ if (!kvm_vcpu_apicv_active(vcpu))
+ return;
+
+ entry = READ_ONCE(*(svm->avic_physical_id_cache));
+ entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
+ WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
}
static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
@@ -1436,10 +1447,10 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
goto free_page4;
}
- /* We initialize this flag to one to make sure that the is_running
+ /* We initialize this flag to true to make sure that the is_running
* bit would be set the first time the vcpu is loaded.
*/
- svm->avic_is_blocking = false;
+ svm->avic_is_running = true;
svm->nested.hsave = page_address(hsave_page);
@@ -1518,7 +1529,7 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
if (static_cpu_has(X86_FEATURE_RDTSCP))
wrmsrl(MSR_TSC_AUX, svm->tsc_aux);
- avic_vcpu_load(vcpu, cpu, true);
+ avic_vcpu_load(vcpu, cpu);
}
static void svm_vcpu_put(struct kvm_vcpu *vcpu)
@@ -1526,7 +1537,7 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu)
struct vcpu_svm *svm = to_svm(vcpu);
int i;
- avic_vcpu_load(vcpu, 0, false);
+ avic_vcpu_put(vcpu);
++vcpu->stat.host_state_reload;
kvm_load_ldt(svm->host.ldt);
@@ -1545,13 +1556,11 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu)
static void svm_vcpu_blocking(struct kvm_vcpu *vcpu)
{
- to_svm(vcpu)->avic_is_blocking = true;
avic_set_running(vcpu, false);
}
static void svm_vcpu_unblocking(struct kvm_vcpu *vcpu)
{
- to_svm(vcpu)->avic_is_blocking = false;
avic_set_running(vcpu, true);
}
The two functions now have the same signature as their callers,
svm_vcpu_load and svm_vcpu_put.
Thanks,
Paolo
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