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commit 391a8b6d20b72c4f24f8511f78ef75a6119cbe22
Author: Paul Durrant <pdurrant@amazon.com>
AuthorDate: Thu Aug 13 11:35:53 2020 +0100
Commit: Andrew Cooper <andrew.cooper3@citrix.com>
CommitDate: Thu Aug 13 12:42:26 2020 +0100

x86/viridian: remove the viridian_vcpu msg_pending bit mask

The mask does not actually serve a useful purpose as we only use the SynIC
for timer messages. Dropping the mask means that the EOM MSR handler
essentially becomes a no-op. This means we can avoid setting 'message_pending'
for timer messages and hence avoid a VMEXIT for the EOM.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Wei Liu <wl@xen.org>
---
xen/arch/x86/hvm/viridian/synic.c | 24 +-----------------------
xen/arch/x86/hvm/vlapic.c | 4 ----
xen/include/asm-x86/hvm/viridian.h | 2 --
3 files changed, 1 insertion(+), 29 deletions(-)

diff --git a/xen/arch/x86/hvm/viridian/synic.c b/xen/arch/x86/hvm/viridian/synic.c
index 94a2b88733..22e2df27e5 100644
--- a/xen/arch/x86/hvm/viridian/synic.c
+++ b/xen/arch/x86/hvm/viridian/synic.c
@@ -137,7 +137,6 @@ int viridian_synic_wrmsr(struct vcpu *v, uint32_t idx, uint64_t val)
if ( !(viridian_feature_mask(d) & HVMPV_synic) )
return X86EMUL_EXCEPTION;

- vv->msg_pending = 0;
break;

case HV_X64_MSR_SINT0 ... HV_X64_MSR_SINT15:
@@ -168,9 +167,6 @@ int viridian_synic_wrmsr(struct vcpu *v, uint32_t idx, uint64_t val)
printk(XENLOG_G_INFO "%pv: VIRIDIAN SINT%u: vector: %x\n", v, sintx,
vector);

- if ( new.polling )
- __clear_bit(sintx, &vv->msg_pending);
-
*vs = new;
break;
}
@@ -334,9 +330,6 @@ bool viridian_synic_deliver_timer_msg(struct vcpu *v, unsigned int sintx,
.DeliveryTime = delivery,
};

- if ( test_bit(sintx, &vv->msg_pending) )
- return false;
-
/*
* To avoid using an atomic test-and-set, and barrier before calling
* vlapic_set_irq(), this function must be called in context of the
@@ -346,12 +339,9 @@ bool viridian_synic_deliver_timer_msg(struct vcpu *v, unsigned int sintx,

msg += sintx;

+ /* There is no need to set message_pending as we do not require an EOM */
if ( msg->header.message_type != HVMSG_NONE )
- {
- msg->header.message_flags.msg_pending = 1;
- __set_bit(sintx, &vv->msg_pending);
return false;
- }

msg->header.message_type = HVMSG_TIMER_EXPIRED;
msg->header.message_flags.msg_pending = 0;
@@ -380,18 +370,6 @@ bool viridian_synic_is_auto_eoi_sint(const struct vcpu *v,
return vs->auto_eoi;
}

-void viridian_synic_ack_sint(const struct vcpu *v, unsigned int vector)
-{
- struct viridian_vcpu *vv = v->arch.hvm.viridian;
- unsigned int sintx = vv->vector_to_sintx[vector];
-
- ASSERT(v == current);
-
- if ( sintx < ARRAY_SIZE(vv->sint) )
- __clear_bit(array_index_nospec(sintx, ARRAY_SIZE(vv->sint)),
- &vv->msg_pending);
-}
-
void viridian_synic_save_vcpu_ctxt(const struct vcpu *v,
struct hvm_viridian_vcpu_context *ctxt)
{
diff --git a/xen/arch/x86/hvm/vlapic.c b/xen/arch/x86/hvm/vlapic.c
index 7b5c633033..4e3861eb7d 100644
--- a/xen/arch/x86/hvm/vlapic.c
+++ b/xen/arch/x86/hvm/vlapic.c
@@ -462,12 +462,8 @@ void vlapic_handle_EOI(struct vlapic *vlapic, u8 vector)
struct vcpu *v = vlapic_vcpu(vlapic);
struct domain *d = v->domain;

- /* All synic SINTx vectors are edge triggered */
-
if ( vlapic_test_vector(vector, &vlapic->regs->data[APIC_TMR]) )
vioapic_update_EOI(d, vector);
- else if ( has_viridian_synic(d) )
- viridian_synic_ack_sint(v, vector);

hvm_dpci_msi_eoi(d, vector);
}
diff --git a/xen/include/asm-x86/hvm/viridian.h b/xen/include/asm-x86/hvm/viridian.h
index 844e56b38f..cbf77d9c76 100644
--- a/xen/include/asm-x86/hvm/viridian.h
+++ b/xen/include/asm-x86/hvm/viridian.h
@@ -31,7 +31,6 @@ struct viridian_vcpu
struct viridian_page vp_assist;
bool apic_assist_pending;
bool polled;
- unsigned int msg_pending;
uint64_t scontrol;
uint64_t siefp;
struct viridian_page simp;
@@ -89,7 +88,6 @@ void viridian_apic_assist_clear(const struct vcpu *v);
void viridian_synic_poll(struct vcpu *v);
bool viridian_synic_is_auto_eoi_sint(const struct vcpu *v,
unsigned int vector);
-void viridian_synic_ack_sint(const struct vcpu *v, unsigned int vector);

#endif /* __ASM_X86_HVM_VIRIDIAN_H__ */

--
generated by git-patchbot for /home/xen/git/xen.git#master