Module Name: src
Committed By: maxv
Date: Thu Jan 10 06:58:37 UTC 2019
Modified Files:
src/sys/dev/nvmm/x86: nvmm_x86_svm.c nvmm_x86_svmfunc.S
Log Message:
Optimize:
* Don't save/restore the host CR2, we don't care because we're not in a
#PF context (and preemption switches already handle CR2 safely).
* Don't save/restore the host FS and GS, just reset them to zero after
VMRUN. Note: DS and ES must be reset _before_ VMRUN, but that doesn't
apply to FS and GS.
* Handle FSBASE and KGSBASE outside of the VCPU loop, to avoid the cost
of saving/restoring them when there's no reason to leave the loop.
To generate a diff of this commit:
cvs rdiff -u -r1.13 -r1.14 src/sys/dev/nvmm/x86/nvmm_x86_svm.c
cvs rdiff -u -r1.1 -r1.2 src/sys/dev/nvmm/x86/nvmm_x86_svmfunc.S
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/nvmm/x86/nvmm_x86_svm.c
diff -u src/sys/dev/nvmm/x86/nvmm_x86_svm.c:1.13 src/sys/dev/nvmm/x86/nvmm_x86_svm.c:1.14
--- src/sys/dev/nvmm/x86/nvmm_x86_svm.c:1.13 Tue Jan 8 14:43:18 2019
+++ src/sys/dev/nvmm/x86/nvmm_x86_svm.c Thu Jan 10 06:58:36 2019
@@ -1,4 +1,4 @@
-/* $NetBSD: nvmm_x86_svm.c,v 1.13 2019/01/08 14:43:18 maxv Exp $ */
+/* $NetBSD: nvmm_x86_svm.c,v 1.14 2019/01/10 06:58:36 maxv Exp $ */
/*
* Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nvmm_x86_svm.c,v 1.13 2019/01/08 14:43:18 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nvmm_x86_svm.c,v 1.14 2019/01/10 06:58:36 maxv Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -521,7 +521,8 @@ struct svm_cpudata {
uint64_t lstar;
uint64_t cstar;
uint64_t sfmask;
- uint64_t cr2;
+ uint64_t fsbase;
+ uint64_t kernelgsbase;
bool ts_set;
struct xsave_header hfpu __aligned(16);
@@ -1151,14 +1152,12 @@ svm_vcpu_guest_misc_enter(struct nvmm_cp
{
struct svm_cpudata *cpudata = vcpu->cpudata;
- /* Save the fixed Host MSRs. */
cpudata->star = rdmsr(MSR_STAR);
cpudata->lstar = rdmsr(MSR_LSTAR);
cpudata->cstar = rdmsr(MSR_CSTAR);
cpudata->sfmask = rdmsr(MSR_SFMASK);
-
- /* Save the Host CR2. */
- cpudata->cr2 = rcr2();
+ cpudata->fsbase = rdmsr(MSR_FSBASE);
+ cpudata->kernelgsbase = rdmsr(MSR_KERNELGSBASE);
}
static void
@@ -1166,14 +1165,12 @@ svm_vcpu_guest_misc_leave(struct nvmm_cp
{
struct svm_cpudata *cpudata = vcpu->cpudata;
- /* Restore the fixed Host MSRs. */
wrmsr(MSR_STAR, cpudata->star);
wrmsr(MSR_LSTAR, cpudata->lstar);
wrmsr(MSR_CSTAR, cpudata->cstar);
wrmsr(MSR_SFMASK, cpudata->sfmask);
-
- /* Restore the Host CR2. */
- lcr2(cpudata->cr2);
+ wrmsr(MSR_FSBASE, cpudata->fsbase);
+ wrmsr(MSR_KERNELGSBASE, cpudata->kernelgsbase);
}
static int
Index: src/sys/dev/nvmm/x86/nvmm_x86_svmfunc.S
diff -u src/sys/dev/nvmm/x86/nvmm_x86_svmfunc.S:1.1 src/sys/dev/nvmm/x86/nvmm_x86_svmfunc.S:1.2
--- src/sys/dev/nvmm/x86/nvmm_x86_svmfunc.S:1.1 Wed Nov 7 07:43:08 2018
+++ src/sys/dev/nvmm/x86/nvmm_x86_svmfunc.S Thu Jan 10 06:58:36 2019
@@ -1,4 +1,4 @@
-/* $NetBSD: nvmm_x86_svmfunc.S,v 1.1 2018/11/07 07:43:08 maxv Exp $ */
+/* $NetBSD: nvmm_x86_svmfunc.S,v 1.2 2019/01/10 06:58:36 maxv Exp $ */
/*
* Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -73,14 +73,6 @@
movq $msr,%rcx ;\
wrmsr
-#define HOST_SAVE_SEGREG(sreg) \
- movw sreg,%ax ;\
- pushw %ax
-
-#define HOST_RESTORE_SEGREG(sreg)\
- popw %ax ;\
- movw %ax,sreg
-
#define HOST_SAVE_TR \
strw %ax ;\
pushw %ax
@@ -150,22 +142,13 @@ ENTRY(svm_vmrun)
/* Save the Host TR. */
HOST_SAVE_TR
- /* Save the variable Host MSRs. */
- HOST_SAVE_MSR(MSR_KERNELGSBASE)
+ /* Save the Host GSBASE. */
HOST_SAVE_MSR(MSR_GSBASE)
- HOST_SAVE_MSR(MSR_FSBASE)
- /* Reset the Host Segregs. */
+ /* Reset DS and ES. */
movq $GSEL(GUDATA_SEL, SEL_UPL),%rax
movw %ax,%ds
movw %ax,%es
- xorq %rax,%rax
- movw %ax,%fs
- movw %ax,%gs
-
- /* Save some Host Segregs. */
- HOST_SAVE_SEGREG(%fs)
- HOST_SAVE_SEGREG(%gs)
/* Save the Host LDT. */
HOST_SAVE_LDT
@@ -195,14 +178,13 @@ ENTRY(svm_vmrun)
/* Restore the Host LDT. */
HOST_RESTORE_LDT
- /* Restore the Host Segregs. */
- HOST_RESTORE_SEGREG(%gs)
- HOST_RESTORE_SEGREG(%fs)
+ /* Reset FS and GS. */
+ xorq %rax,%rax
+ movw %ax,%fs
+ movw %ax,%gs
- /* Restore the variable Host MSRs. */
- HOST_RESTORE_MSR(MSR_FSBASE)
+ /* Restore the Host GSBASE. */
HOST_RESTORE_MSR(MSR_GSBASE)
- HOST_RESTORE_MSR(MSR_KERNELGSBASE)
/* Restore the Host TR. */
HOST_RESTORE_TR
