From 74ac712f72cfd6d7b3db3c9d3b72ccf2824aa183 Mon Sep 17 00:00:00 2001
From: Mark Johnston <markj@FreeBSD.org>
Date: Wed, 26 Apr 2023 10:08:42 -0400
Subject: [PATCH] vmm: Dynamically allocate a couple of per-CPU state save
 areas

This avoids bloating the BSS when MAXCPU is large.

No functional change intended.

PR:		269572
Reviewed by:	corvink, rew
Tested by:	rew
MFC after:	2 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D39805
---
 sys/amd64/vmm/amd/svm.c   | 11 ++++++-----
 sys/amd64/vmm/intel/vmx.c | 12 ++++++++----
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/sys/amd64/vmm/amd/svm.c b/sys/amd64/vmm/amd/svm.c
index d995b68ebdc6..0af7342128f2 100644
--- a/sys/amd64/vmm/amd/svm.c
+++ b/sys/amd64/vmm/amd/svm.c
@@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/sysctl.h>
 
 #include <vm/vm.h>
+#include <vm/vm_extern.h>
 #include <vm/pmap.h>
 
 #include <machine/cpufunc.h>
@@ -123,10 +124,8 @@ SYSCTL_UINT(_hw_vmm_svm, OID_AUTO, num_asids, CTLFLAG_RDTUN, &nasid, 0,
 /* Current ASID generation for each host cpu */
 static struct asid asid[MAXCPU];
 
-/* 
- * SVM host state saved area of size 4KB for each core.
- */
-static uint8_t hsave[MAXCPU][PAGE_SIZE] __aligned(PAGE_SIZE);
+/* SVM host state saved area of size 4KB for each physical core. */
+static uint8_t *hsave;
 
 static VMM_STAT_AMD(VCPU_EXITINTINFO, "VM exits during event delivery");
 static VMM_STAT_AMD(VCPU_INTINFO_INJECTED, "Events pending at VM entry");
@@ -167,6 +166,7 @@ svm_modcleanup(void)
 {
 
 	smp_rendezvous(NULL, svm_disable, NULL, NULL);
+	kmem_free(hsave, (mp_maxid + 1) * PAGE_SIZE);
 	return (0);
 }
 
@@ -214,7 +214,7 @@ svm_enable(void *arg __unused)
 	efer |= EFER_SVM;
 	wrmsr(MSR_EFER, efer);
 
-	wrmsr(MSR_VM_HSAVE_PA, vtophys(hsave[curcpu]));
+	wrmsr(MSR_VM_HSAVE_PA, vtophys(&hsave[curcpu * PAGE_SIZE]));
 }
 
 /*
@@ -269,6 +269,7 @@ svm_modinit(int ipinum)
 	svm_npt_init(ipinum);
 
 	/* Enable SVM on all CPUs */
+	hsave = kmem_malloc((mp_maxid + 1) * PAGE_SIZE, M_WAITOK | M_ZERO);
 	smp_rendezvous(NULL, svm_enable, NULL, NULL);
 
 	return (0);
diff --git a/sys/amd64/vmm/intel/vmx.c b/sys/amd64/vmm/intel/vmx.c
index 32e53de4e8ee..55ed5fdf1a00 100644
--- a/sys/amd64/vmm/intel/vmx.c
+++ b/sys/amd64/vmm/intel/vmx.c
@@ -46,6 +46,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/sysctl.h>
 
 #include <vm/vm.h>
+#include <vm/vm_extern.h>
 #include <vm/pmap.h>
 
 #include <machine/psl.h>
@@ -134,7 +135,7 @@ SYSCTL_NODE(_hw_vmm, OID_AUTO, vmx, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL,
     NULL);
 
 int vmxon_enabled[MAXCPU];
-static char vmxon_region[MAXCPU][PAGE_SIZE] __aligned(PAGE_SIZE);
+static uint8_t *vmxon_region;
 
 static uint32_t pinbased_ctls, procbased_ctls, procbased_ctls2;
 static uint32_t exit_ctls, entry_ctls;
@@ -618,6 +619,7 @@ vmx_modcleanup(void)
 		nmi_flush_l1d_sw = 0;
 
 	smp_rendezvous(NULL, vmx_disable, NULL, NULL);
+	kmem_free(vmxon_region, (mp_maxid + 1) * PAGE_SIZE);
 
 	return (0);
 }
@@ -638,8 +640,8 @@ vmx_enable(void *arg __unused)
 
 	load_cr4(rcr4() | CR4_VMXE);
 
-	*(uint32_t *)vmxon_region[curcpu] = vmx_revision();
-	error = vmxon(vmxon_region[curcpu]);
+	*(uint32_t *)&vmxon_region[curcpu * PAGE_SIZE] = vmx_revision();
+	error = vmxon(&vmxon_region[curcpu * PAGE_SIZE]);
 	if (error == 0)
 		vmxon_enabled[curcpu] = 1;
 }
@@ -649,7 +651,7 @@ vmx_modresume(void)
 {
 
 	if (vmxon_enabled[curcpu])
-		vmxon(vmxon_region[curcpu]);
+		vmxon(&vmxon_region[curcpu * PAGE_SIZE]);
 }
 
 static int
@@ -953,6 +955,8 @@ vmx_modinit(int ipinum)
 	vmx_msr_init();
 
 	/* enable VMX operation */
+	vmxon_region = kmem_malloc((mp_maxid + 1) * PAGE_SIZE,
+	    M_WAITOK | M_ZERO);
 	smp_rendezvous(NULL, vmx_enable, NULL, NULL);
 
 	vmx_initialized = 1;