git: ceb0d0b0f184 - main - bhyve: Remove some no-op code for setting RIP.

From: John Baldwin <jhb_at_FreeBSD.org>
Date: Wed, 21 Dec 2022 18:34:03 UTC
The branch main has been updated by jhb:

URL: https://cgit.FreeBSD.org/src/commit/?id=ceb0d0b0f184d72f31ebdaa4edc752aed78a5807

commit ceb0d0b0f184d72f31ebdaa4edc752aed78a5807
Author:     John Baldwin <jhb@FreeBSD.org>
AuthorDate: 2022-12-21 18:32:24 +0000
Commit:     John Baldwin <jhb@FreeBSD.org>
CommitDate: 2022-12-21 18:32:24 +0000

    bhyve: Remove some no-op code for setting RIP.
    
    fbsdrun_addcpu() read the current vCPU's RIP register from the kernel
    via vm_get_register() to pass along through some layers to vm_loop()
    which then set the register via vm_set_register().  However, this is
    just always setting the value back to itself.
    
    Reviewed by:    corvink
    Differential Revision:  https://reviews.freebsd.org/D37643
---
 usr.sbin/bhyve/bhyverun.c | 24 +++++-------------------
 1 file changed, 5 insertions(+), 19 deletions(-)

diff --git a/usr.sbin/bhyve/bhyverun.c b/usr.sbin/bhyve/bhyverun.c
index 72f806e97993..e40229e79828 100644
--- a/usr.sbin/bhyve/bhyverun.c
+++ b/usr.sbin/bhyve/bhyverun.c
@@ -194,7 +194,7 @@ static const int BSP = 0;
 
 static cpuset_t cpumask;
 
-static void vm_loop(struct vmctx *ctx, int vcpu, uint64_t rip);
+static void vm_loop(struct vmctx *ctx, int vcpu);
 
 static struct vm_exit *vmexit;
 
@@ -540,7 +540,7 @@ fbsdrun_start_thread(void *param)
 #endif
 	gdb_cpu_add(vcpu);
 
-	vm_loop(mtp->mt_ctx, vcpu, vmexit[vcpu].rip);
+	vm_loop(mtp->mt_ctx, vcpu);
 
 	/* not reached */
 	exit(1);
@@ -548,7 +548,7 @@ fbsdrun_start_thread(void *param)
 }
 
 static void
-fbsdrun_addcpu(struct vmctx *ctx, int newcpu, uint64_t rip, bool suspend)
+fbsdrun_addcpu(struct vmctx *ctx, int newcpu, bool suspend)
 {
 	int error;
 
@@ -561,13 +561,6 @@ fbsdrun_addcpu(struct vmctx *ctx, int newcpu, uint64_t rip, bool suspend)
 	if (suspend)
 		vm_suspend_cpu(ctx, newcpu);
 
-	/*
-	 * Set up the vmexit struct to allow execution to start
-	 * at the given RIP
-	 */
-	vmexit[newcpu].rip = rip;
-	vmexit[newcpu].inst_length = 0;
-
 	mt_vmm_info[newcpu].mt_ctx = ctx;
 	mt_vmm_info[newcpu].mt_vcpu = newcpu;
 
@@ -973,7 +966,7 @@ static vmexit_handler_t handler[VM_EXITCODE_MAX] = {
 };
 
 static void
-vm_loop(struct vmctx *ctx, int vcpu, uint64_t startrip)
+vm_loop(struct vmctx *ctx, int vcpu)
 {
 	int error, rc;
 	enum vm_exitcode exitcode;
@@ -988,9 +981,6 @@ vm_loop(struct vmctx *ctx, int vcpu, uint64_t startrip)
 	error = vm_active_cpus(ctx, &active_cpus);
 	assert(CPU_ISSET(vcpu, &active_cpus));
 
-	error = vm_set_register(ctx, vcpu, VM_REG_GUEST_RIP, startrip);
-	assert(error == 0);
-
 	while (1) {
 		error = vm_run(ctx, vcpu, &vmexit[vcpu]);
 		if (error != 0)
@@ -1152,7 +1142,6 @@ static void
 spinup_vcpu(struct vmctx *ctx, int vcpu, bool suspend)
 {
 	int error;
-	uint64_t rip;
 
 	if (vcpu != BSP) {
 		fbsdrun_set_capabilities(ctx, vcpu);
@@ -1166,10 +1155,7 @@ spinup_vcpu(struct vmctx *ctx, int vcpu, bool suspend)
 		assert(error == 0);
 	}
 
-	error = vm_get_register(ctx, vcpu, VM_REG_GUEST_RIP, &rip);
-	assert(error == 0);
-
-	fbsdrun_addcpu(ctx, vcpu, rip, suspend);
+	fbsdrun_addcpu(ctx, vcpu, suspend);
 }
 
 static bool