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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v8 08/13] x86/hvm: split I/O completion handling from state model
The state of in-flight I/O and how its completion will be handled are
logically separate and conflating the two makes the code unnecessarily
confusing.
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
Cc: Keir Fraser <keir@xxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
v8:
- No change
v7:
- Modified struct field placement as requested by Jan
v6:
- Added Andrew's reviewed-by
v5:
- Confirmed call to msix_write_completion() is in the correct place.
---
xen/arch/x86/hvm/hvm.c | 44 +++++++++++++++++++++++++++----------
xen/arch/x86/hvm/io.c | 6 ++---
xen/arch/x86/hvm/vmx/realmode.c | 27 +++++++++++++++++------
xen/include/asm-x86/hvm/vcpu.h | 16 +++++++++-----
xen/include/asm-x86/hvm/vmx/vmx.h | 1 +
5 files changed, 67 insertions(+), 27 deletions(-)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 7358acf..093a710 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -59,6 +59,7 @@
#include <asm/hvm/trace.h>
#include <asm/hvm/nestedhvm.h>
#include <asm/hvm/event.h>
+#include <asm/hvm/vmx/vmx.h>
#include <asm/mtrr.h>
#include <asm/apic.h>
#include <public/sched.h>
@@ -428,17 +429,6 @@ static void hvm_io_assist(ioreq_t *p)
vio->io_state = HVMIO_completed;
vio->io_data = p->data;
break;
- case HVMIO_handle_mmio_awaiting_completion:
- vio->io_state = HVMIO_completed;
- vio->io_data = p->data;
- (void)handle_mmio();
- break;
- case HVMIO_handle_pio_awaiting_completion:
- if ( vio->io_size == 4 ) /* Needs zero extension. */
- guest_cpu_user_regs()->rax = (uint32_t)p->data;
- else
- memcpy(&guest_cpu_user_regs()->rax, &p->data, vio->io_size);
- break;
default:
break;
}
@@ -479,6 +469,7 @@ void hvm_do_resume(struct vcpu *v)
struct hvm_vcpu_io *vio = &v->arch.hvm_vcpu.hvm_io;
struct domain *d = v->domain;
struct hvm_ioreq_server *s;
+ enum hvm_io_completion io_completion;
check_wakeup_from_wait();
@@ -505,8 +496,37 @@ void hvm_do_resume(struct vcpu *v)
}
}
- if ( vio->mmio_retry )
+ io_completion = vio->io_completion;
+ vio->io_completion = HVMIO_no_completion;
+
+ switch ( io_completion )
+ {
+ case HVMIO_no_completion:
+ break;
+ case HVMIO_mmio_completion:
handle_mmio();
+ break;
+ case HVMIO_pio_completion:
+ if ( vio->io_size == 4 ) /* Needs zero extension. */
+ guest_cpu_user_regs()->rax = (uint32_t)vio->io_data;
+ else
+ memcpy(&guest_cpu_user_regs()->rax, &vio->io_data, vio->io_size);
+ vio->io_state = HVMIO_none;
+ break;
+ case HVMIO_realmode_completion:
+ {
+ struct hvm_emulate_ctxt ctxt;
+
+ hvm_emulate_prepare(&ctxt, guest_cpu_user_regs());
+ vmx_realmode_emulate_one(&ctxt);
+ hvm_emulate_writeback(&ctxt);
+
+ break;
+ }
+ default:
+ ASSERT_UNREACHABLE();
+ break;
+ }
/* Inject pending hw/sw trap */
if ( v->arch.hvm_vcpu.inject_trap.vector != -1 )
diff --git a/xen/arch/x86/hvm/io.c b/xen/arch/x86/hvm/io.c
index fe099d8..221d05e 100644
--- a/xen/arch/x86/hvm/io.c
+++ b/xen/arch/x86/hvm/io.c
@@ -92,8 +92,8 @@ int handle_mmio(void)
if ( rc != X86EMUL_RETRY )
vio->io_state = HVMIO_none;
- if ( vio->io_state == HVMIO_awaiting_completion )
- vio->io_state = HVMIO_handle_mmio_awaiting_completion;
+ if ( vio->io_state == HVMIO_awaiting_completion || vio->mmio_retry )
+ vio->io_completion = HVMIO_mmio_completion;
else
vio->mmio_access = (struct npfec){};
@@ -158,7 +158,7 @@ int handle_pio(uint16_t port, unsigned int size, int dir)
return 0;
/* Completion in hvm_io_assist() with no re-emulation required. */
ASSERT(dir == IOREQ_READ);
- vio->io_state = HVMIO_handle_pio_awaiting_completion;
+ vio->io_completion = HVMIO_pio_completion;
break;
default:
gdprintk(XENLOG_ERR, "Weird HVM ioemulation status %d.\n", rc);
diff --git a/xen/arch/x86/hvm/vmx/realmode.c b/xen/arch/x86/hvm/vmx/realmode.c
index fe8b4a0..76ff9a5 100644
--- a/xen/arch/x86/hvm/vmx/realmode.c
+++ b/xen/arch/x86/hvm/vmx/realmode.c
@@ -101,15 +101,19 @@ static void realmode_deliver_exception(
}
}
-static void realmode_emulate_one(struct hvm_emulate_ctxt *hvmemul_ctxt)
+void vmx_realmode_emulate_one(struct hvm_emulate_ctxt *hvmemul_ctxt)
{
struct vcpu *curr = current;
+ struct hvm_vcpu_io *vio = &curr->arch.hvm_vcpu.hvm_io;
int rc;
perfc_incr(realmode_emulations);
rc = hvm_emulate_one(hvmemul_ctxt);
+ if ( vio->io_state == HVMIO_awaiting_completion || vio->mmio_retry )
+ vio->io_completion = HVMIO_realmode_completion;
+
if ( rc == X86EMUL_UNHANDLEABLE )
{
gdprintk(XENLOG_ERR, "Failed to emulate insn.\n");
@@ -177,9 +181,6 @@ void vmx_realmode(struct cpu_user_regs *regs)
hvm_emulate_prepare(&hvmemul_ctxt, regs);
- if ( vio->io_state == HVMIO_completed )
- realmode_emulate_one(&hvmemul_ctxt);
-
/* Only deliver interrupts into emulated real mode. */
if ( !(curr->arch.hvm_vcpu.guest_cr[0] & X86_CR0_PE) &&
(intr_info & INTR_INFO_VALID_MASK) )
@@ -190,8 +191,7 @@ void vmx_realmode(struct cpu_user_regs *regs)
curr->arch.hvm_vmx.vmx_emulate = 1;
while ( curr->arch.hvm_vmx.vmx_emulate &&
- !softirq_pending(smp_processor_id()) &&
- (vio->io_state == HVMIO_none) )
+ !softirq_pending(smp_processor_id()) )
{
/*
* Check for pending interrupts only every 16 instructions, because
@@ -203,7 +203,10 @@ void vmx_realmode(struct cpu_user_regs *regs)
hvm_local_events_need_delivery(curr) )
break;
- realmode_emulate_one(&hvmemul_ctxt);
+ vmx_realmode_emulate_one(&hvmemul_ctxt);
+
+ if ( vio->io_state != HVMIO_none || vio->mmio_retry )
+ break;
/* Stop emulating unless our segment state is not safe */
if ( curr->arch.hvm_vmx.vmx_realmode )
@@ -245,3 +248,13 @@ void vmx_realmode(struct cpu_user_regs *regs)
if ( intr_info & INTR_INFO_VALID_MASK )
__vmwrite(VM_ENTRY_INTR_INFO, intr_info);
}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-x86/hvm/vcpu.h b/xen/include/asm-x86/hvm/vcpu.h
index bf6c7ab..5564fba 100644
--- a/xen/include/asm-x86/hvm/vcpu.h
+++ b/xen/include/asm-x86/hvm/vcpu.h
@@ -34,11 +34,16 @@ enum hvm_io_state {
HVMIO_none = 0,
HVMIO_dispatched,
HVMIO_awaiting_completion,
- HVMIO_handle_mmio_awaiting_completion,
- HVMIO_handle_pio_awaiting_completion,
HVMIO_completed
};
+enum hvm_io_completion {
+ HVMIO_no_completion,
+ HVMIO_mmio_completion,
+ HVMIO_pio_completion,
+ HVMIO_realmode_completion
+};
+
struct hvm_vcpu_asid {
uint64_t generation;
uint32_t asid;
@@ -46,9 +51,10 @@ struct hvm_vcpu_asid {
struct hvm_vcpu_io {
/* I/O request in flight to device model. */
- enum hvm_io_state io_state;
- unsigned long io_data;
- int io_size;
+ enum hvm_io_state io_state;
+ enum hvm_io_completion io_completion;
+ unsigned long io_data;
+ unsigned int io_size;
/*
* HVM emulation:
diff --git a/xen/include/asm-x86/hvm/vmx/vmx.h
b/xen/include/asm-x86/hvm/vmx/vmx.h
index 35f804a..c5f3d24 100644
--- a/xen/include/asm-x86/hvm/vmx/vmx.h
+++ b/xen/include/asm-x86/hvm/vmx/vmx.h
@@ -94,6 +94,7 @@ void vmx_asm_do_vmentry(void);
void vmx_intr_assist(void);
void noreturn vmx_do_resume(struct vcpu *);
void vmx_vlapic_msr_changed(struct vcpu *v);
+void vmx_realmode_emulate_one(struct hvm_emulate_ctxt *hvmemul_ctxt);
void vmx_realmode(struct cpu_user_regs *regs);
void vmx_update_debug_state(struct vcpu *v);
void vmx_update_exception_bitmap(struct vcpu *v);
--
1.7.10.4
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