svn commit: r241921 - projects/bhyve/sys/amd64/vmm/intel
Neel Natu
neel at FreeBSD.org
Tue Oct 23 02:20:42 UTC 2012
Author: neel
Date: Tue Oct 23 02:20:42 2012
New Revision: 241921
URL: http://svn.freebsd.org/changeset/base/241921
Log:
Test for AST pending with interrupts disabled right before entering the guest.
If an IPI was delivered to this cpu before interrupts were disabled
then return right away via vmx_setjmp() with a return value of VMX_RETURN_AST.
Obtained from: NetApp
Modified:
projects/bhyve/sys/amd64/vmm/intel/vmx.c
projects/bhyve/sys/amd64/vmm/intel/vmx.h
projects/bhyve/sys/amd64/vmm/intel/vmx_genassym.c
projects/bhyve/sys/amd64/vmm/intel/vmx_support.S
Modified: projects/bhyve/sys/amd64/vmm/intel/vmx.c
==============================================================================
--- projects/bhyve/sys/amd64/vmm/intel/vmx.c Tue Oct 23 02:20:11 2012 (r241920)
+++ projects/bhyve/sys/amd64/vmm/intel/vmx.c Tue Oct 23 02:20:42 2012 (r241921)
@@ -290,6 +290,8 @@ vmx_setjmp_rc2str(int rc)
return "vmresume";
case VMX_RETURN_VMLAUNCH:
return "vmlaunch";
+ case VMX_RETURN_AST:
+ return "ast";
default:
return "unknown";
}
@@ -798,15 +800,20 @@ vmx_run_trace(struct vmx *vmx, int vcpu)
static __inline void
vmx_exit_trace(struct vmx *vmx, int vcpu, uint64_t rip, uint32_t exit_reason,
- int handled, int astpending)
+ int handled)
{
#ifdef KTR
VMM_CTR3(vmx->vm, vcpu, "%s %s vmexit at 0x%0lx",
handled ? "handled" : "unhandled",
exit_reason_to_str(exit_reason), rip);
+#endif
+}
- if (astpending)
- VMM_CTR0(vmx->vm, vcpu, "astpending");
+static __inline void
+vmx_astpending_trace(struct vmx *vmx, int vcpu, uint64_t rip)
+{
+#ifdef KTR
+ VMM_CTR1(vmx->vm, vcpu, "astpending vmexit at 0x%0lx", rip);
#endif
}
@@ -981,19 +988,19 @@ vmx_inject_interrupts(struct vmx *vmx, i
const int HWINTR_BLOCKED = VMCS_INTERRUPTIBILITY_STI_BLOCKING |
VMCS_INTERRUPTIBILITY_MOVSS_BLOCKING;
-#if 1
/*
- * XXX
- * If an event is being injected from userland then just return.
- * For e.g. we may inject a breakpoint exception to cause the
- * guest to enter the debugger so we can inspect its state.
+ * If there is already an interrupt pending then just return.
+ *
+ * This could happen if an interrupt was injected on a prior
+ * VM entry but the actual entry into guest mode was aborted
+ * because of a pending AST.
*/
error = vmread(VMCS_ENTRY_INTR_INFO, &info);
if (error)
panic("vmx_inject_interrupts: vmread(intrinfo) %d", error);
if (info & VMCS_INTERRUPTION_INFO_VALID)
return;
-#endif
+
/*
* NMI injection has priority so deal with those first
*/
@@ -1301,7 +1308,7 @@ vmx_exit_process(struct vmx *vmx, int vc
/*
* It is possible that control is returned to userland
* even though we were able to handle the VM exit in the
- * kernel (for e.g. 'astpending' is set in the run loop).
+ * kernel.
*
* In such a case we want to make sure that the userland
* restarts guest execution at the instruction *after*
@@ -1352,6 +1359,7 @@ vmx_run(void *arg, int vcpu, register_t
vmxctx = &vmx->ctx[vcpu];
vmxctx->launched = 0;
+ astpending = 0;
vmexit = vm_exitinfo(vmx->vm, vcpu);
/*
@@ -1395,6 +1403,9 @@ vmx_run(void *arg, int vcpu, register_t
break;
case VMX_RETURN_LONGJMP:
break; /* vm exit */
+ case VMX_RETURN_AST:
+ astpending = 1;
+ break;
case VMX_RETURN_VMRESUME:
vie = vmcs_instruction_error();
if (vmxctx->launch_error == VM_FAIL_INVALID ||
@@ -1417,14 +1428,6 @@ vmx_run(void *arg, int vcpu, register_t
panic("vmx_setjmp returned %d", rc);
}
- /*
- * XXX locking?
- * See comments in exception.S about checking for ASTs
- * atomically while interrupts are disabled. But it is
- * not clear that they apply in our case.
- */
- astpending = curthread->td_flags & TDF_ASTPENDING;
-
/* enable interrupts */
enable_intr();
@@ -1434,11 +1437,18 @@ vmx_run(void *arg, int vcpu, register_t
vmexit->u.vmx.exit_reason = exit_reason = vmcs_exit_reason();
vmexit->u.vmx.exit_qualification = vmcs_exit_qualification();
+ if (astpending) {
+ handled = 1;
+ vmexit->inst_length = 0;
+ vmexit->exitcode = VM_EXITCODE_BOGUS;
+ vmx_astpending_trace(vmx, vcpu, rip);
+ break;
+ }
+
handled = vmx_exit_process(vmx, vcpu, vmexit);
+ vmx_exit_trace(vmx, vcpu, rip, exit_reason, handled);
- vmx_exit_trace(vmx, vcpu, rip, exit_reason, handled,
- astpending);
- } while (handled && !astpending);
+ } while (handled);
/*
* If a VM exit has been handled then the exitcode must be BOGUS
@@ -1646,7 +1656,7 @@ vmx_inject(void *arg, int vcpu, int type
int code_valid)
{
int error;
- uint32_t info;
+ uint64_t info;
struct vmx *vmx = arg;
struct vmcs *vmcs = &vmx->vmcs[vcpu];
@@ -1660,6 +1670,17 @@ vmx_inject(void *arg, int vcpu, int type
0x6, /* VM_SW_EXCEPTION */
};
+ /*
+ * If there is already an exception pending to be delivered to the
+ * vcpu then just return.
+ */
+ error = vmcs_getreg(vmcs, VMCS_ENTRY_INTR_INFO, &info);
+ if (error)
+ return (error);
+
+ if (info & VMCS_INTERRUPTION_INFO_VALID)
+ return (EAGAIN);
+
info = vector | (type_map[type] << 8) | (code_valid ? 1 << 11 : 0);
info |= VMCS_INTERRUPTION_INFO_VALID;
error = vmcs_setreg(vmcs, VMCS_IDENT(VMCS_ENTRY_INTR_INFO), info);
Modified: projects/bhyve/sys/amd64/vmm/intel/vmx.h
==============================================================================
--- projects/bhyve/sys/amd64/vmm/intel/vmx.h Tue Oct 23 02:20:11 2012 (r241920)
+++ projects/bhyve/sys/amd64/vmm/intel/vmx.h Tue Oct 23 02:20:42 2012 (r241921)
@@ -101,12 +101,14 @@ CTASSERT((offsetof(struct vmx, guest_msr
#define VMX_RETURN_LONGJMP 1
#define VMX_RETURN_VMRESUME 2
#define VMX_RETURN_VMLAUNCH 3
+#define VMX_RETURN_AST 4
/*
* vmx_setjmp() returns:
* - 0 when it returns directly
* - 1 when it returns from vmx_longjmp
* - 2 when it returns from vmx_resume (which would only be in the error case)
* - 3 when it returns from vmx_launch (which would only be in the error case)
+ * - 4 when it returns from vmx_resume or vmx_launch because of AST pending
*/
int vmx_setjmp(struct vmxctx *ctx);
void vmx_longjmp(void); /* returns via vmx_setjmp */
Modified: projects/bhyve/sys/amd64/vmm/intel/vmx_genassym.c
==============================================================================
--- projects/bhyve/sys/amd64/vmm/intel/vmx_genassym.c Tue Oct 23 02:20:11 2012 (r241920)
+++ projects/bhyve/sys/amd64/vmm/intel/vmx_genassym.c Tue Oct 23 02:20:42 2012 (r241921)
@@ -32,6 +32,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
+#include <sys/proc.h>
#include <sys/assym.h>
#include <vm/vm.h>
@@ -80,3 +81,9 @@ ASSYM(VMX_RETURN_DIRECT, VMX_RETURN_DIRE
ASSYM(VMX_RETURN_LONGJMP, VMX_RETURN_LONGJMP);
ASSYM(VMX_RETURN_VMRESUME, VMX_RETURN_VMRESUME);
ASSYM(VMX_RETURN_VMLAUNCH, VMX_RETURN_VMLAUNCH);
+ASSYM(VMX_RETURN_AST, VMX_RETURN_AST);
+
+ASSYM(TDF_ASTPENDING, TDF_ASTPENDING);
+ASSYM(TDF_NEEDRESCHED, TDF_NEEDRESCHED);
+ASSYM(TD_FLAGS, offsetof(struct thread, td_flags));
+ASSYM(PC_CURTHREAD, offsetof(struct pcpu, pc_curthread));
Modified: projects/bhyve/sys/amd64/vmm/intel/vmx_support.S
==============================================================================
--- projects/bhyve/sys/amd64/vmm/intel/vmx_support.S Tue Oct 23 02:20:11 2012 (r241920)
+++ projects/bhyve/sys/amd64/vmm/intel/vmx_support.S Tue Oct 23 02:20:42 2012 (r241921)
@@ -31,6 +31,32 @@
#include "vmx_assym.s"
/*
+ * Disable interrupts before updating %rsp in VMX_CHECK_AST or
+ * VMX_GUEST_RESTORE.
+ *
+ * The location that %rsp points to is a 'vmxctx' and not a
+ * real stack so we don't want an interrupt handler to trash it
+ */
+#define VMX_DISABLE_INTERRUPTS cli
+
+/*
+ * If the thread hosting the vcpu has an ast pending then take care of it
+ * by returning from vmx_setjmp() with a return value of VMX_RETURN_AST.
+ *
+ * Assumes that %rdi holds a pointer to the 'vmxctx' and that interrupts
+ * are disabled.
+ */
+#define VMX_CHECK_AST \
+ movq PCPU(CURTHREAD),%rax; \
+ testl $TDF_ASTPENDING | TDF_NEEDRESCHED,TD_FLAGS(%rax); \
+ je 9f; \
+ movq $VMX_RETURN_AST,%rsi; \
+ movq %rdi,%rsp; \
+ addq $VMXCTX_TMPSTKTOP,%rsp; \
+ callq vmx_return; \
+9:
+
+/*
* Assumes that %rdi holds a pointer to the 'vmxctx'.
*
* On "return" all registers are updated to reflect guest state. The two
@@ -41,12 +67,6 @@
* host context in case of an error with 'vmlaunch' or 'vmresume'.
*/
#define VMX_GUEST_RESTORE \
- /* \
- * Disable interrupts before updating %rsp. The location that \
- * %rsp points to is a 'vmxctx' and not a real stack so we \
- * don't want an interrupt handler to trash it. \
- */ \
- cli; \
movq %rdi,%rsp; \
movq VMXCTX_GUEST_CR2(%rdi),%rsi; \
movq %rsi,%cr2; \
@@ -169,6 +189,10 @@ END(vmx_longjmp)
* through vmx_setjmp() with a return value of 2.
*/
ENTRY(vmx_resume)
+ VMX_DISABLE_INTERRUPTS
+
+ VMX_CHECK_AST
+
/*
* Restore guest state that is not automatically loaded from the vmcs.
*/
@@ -197,6 +221,10 @@ END(vmx_resume)
* through vmx_setjmp() with a return value of 3.
*/
ENTRY(vmx_launch)
+ VMX_DISABLE_INTERRUPTS
+
+ VMX_CHECK_AST
+
/*
* Restore guest state that is not automatically loaded from the vmcs.
*/
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