Introduce enable_msr_interception API to init msr_bitmap, based on it
pKVM can setup the virtual MSR list which need to be trapped and
emulated in the hypervisor.
Signed-off-by: Chuanxiao Dong <chuanxiao.dong@xxxxxxxxx>
Signed-off-by: Jason Chen CJ <jason.cj.chen@xxxxxxxxx>
---
arch/x86/kvm/vmx/pkvm/hyp/Makefile | 2 +-
arch/x86/kvm/vmx/pkvm/hyp/vmexit.c | 13 +----
arch/x86/kvm/vmx/pkvm/hyp/vmsr.c | 73 ++++++++++++++++++++++++++++
arch/x86/kvm/vmx/pkvm/hyp/vmsr.h | 11 +++++
arch/x86/kvm/vmx/pkvm/include/pkvm.h | 2 +
arch/x86/kvm/vmx/pkvm/pkvm_host.c | 1 +
6 files changed, 89 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kvm/vmx/pkvm/hyp/Makefile b/arch/x86/kvm/vmx/pkvm/hyp/Makefile
index ca6d43509ddc..fc75cdd9fc79 100644
--- a/arch/x86/kvm/vmx/pkvm/hyp/Makefile
+++ b/arch/x86/kvm/vmx/pkvm/hyp/Makefile
@@ -12,7 +12,7 @@ ccflags-y += -D__PKVM_HYP__
virt-dir := ../../../../../../$(KVM_PKVM)
pkvm-hyp-y := vmx_asm.o vmexit.o memory.o early_alloc.o pgtable.o mmu.o pkvm.o \
- init_finalise.o ept.o idt.o irq.o nested.o vmx.o
+ init_finalise.o ept.o idt.o irq.o nested.o vmx.o vmsr.o
ifndef CONFIG_PKVM_INTEL_DEBUG
lib-dir := lib
diff --git a/arch/x86/kvm/vmx/pkvm/hyp/vmexit.c b/arch/x86/kvm/vmx/pkvm/hyp/vmexit.c
index 8e7392010887..307514f44ec9 100644
--- a/arch/x86/kvm/vmx/pkvm/hyp/vmexit.c
+++ b/arch/x86/kvm/vmx/pkvm/hyp/vmexit.c
@@ -9,6 +9,7 @@
#include "vmexit.h"
#include "ept.h"
#include "pkvm_hyp.h"
+#include "vmsr.h"
#include "nested.h"
#include "debug.h"
@@ -109,18 +110,6 @@ static unsigned long handle_vmcall(struct kvm_vcpu *vcpu)
return ret;
}
-static void handle_read_msr(struct kvm_vcpu *vcpu)
-{
- /* simply return 0 for non-supported MSRs */
- vcpu->arch.regs[VCPU_REGS_RAX] = 0;
- vcpu->arch.regs[VCPU_REGS_RDX] = 0;
-}
-
-static void handle_write_msr(struct kvm_vcpu *vcpu)
-{
- /*No emulation for msr write now*/
-}
-
static void handle_xsetbv(struct kvm_vcpu *vcpu)
{
u32 eax = (u32)(vcpu->arch.regs[VCPU_REGS_RAX] & -1u);
diff --git a/arch/x86/kvm/vmx/pkvm/hyp/vmsr.c b/arch/x86/kvm/vmx/pkvm/hyp/vmsr.c
new file mode 100644
index 000000000000..360b0333b84f
--- /dev/null
+++ b/arch/x86/kvm/vmx/pkvm/hyp/vmsr.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/*
+ * Copyright (C) 2018-2022 Intel Corporation
+ */
+
+#include <pkvm.h>
+#include "cpu.h"
+#include "debug.h"
+
+#define INTERCEPT_DISABLE (0U)
+#define INTERCEPT_READ (1U << 0U)
+#define INTERCEPT_WRITE (1U << 1U)
+#define INTERCEPT_READ_WRITE (INTERCEPT_READ | INTERCEPT_WRITE)
+
+static unsigned int emulated_ro_guest_msrs[] = {
+ /* DUMMY */
+};
+
+static void enable_msr_interception(u8 *bitmap, unsigned int msr_arg, unsigned int mode)
+{
+ unsigned int read_offset = 0U;
+ unsigned int write_offset = 2048U;
+ unsigned int msr = msr_arg;
+ u8 msr_bit;
+ unsigned int msr_index;
+
+ if ((msr <= 0x1FFFU) || ((msr >= 0xc0000000U) && (msr <= 0xc0001fffU))) {
+ if ((msr & 0xc0000000U) != 0U) {
+ read_offset = read_offset + 1024U;
+ write_offset = write_offset + 1024U;
+ }
+
+ msr &= 0x1FFFU;
+ msr_bit = (u8)(1U << (msr & 0x7U));
+ msr_index = msr >> 3U;
+
+ if ((mode & INTERCEPT_READ) == INTERCEPT_READ)
+ bitmap[read_offset + msr_index] |= msr_bit;
+ else
+ bitmap[read_offset + msr_index] &= ~msr_bit;
+
+ if ((mode & INTERCEPT_WRITE) == INTERCEPT_WRITE)
+ bitmap[write_offset + msr_index] |= msr_bit;
+ else
+ bitmap[write_offset + msr_index] &= ~msr_bit;
+ } else {
+ pkvm_err("%s, Invalid MSR: 0x%x", __func__, msr);
+ }
+}
+
+int handle_read_msr(struct kvm_vcpu *vcpu)
+{
+ /* simply return 0 for non-supported MSRs */
+ vcpu->arch.regs[VCPU_REGS_RAX] = 0;
+ vcpu->arch.regs[VCPU_REGS_RDX] = 0;
+
+ return 0;
+}
+
+int handle_write_msr(struct kvm_vcpu *vcpu)
+{
+ /*No emulation for msr write now*/
+ return 0;
+}
+
+void init_msr_emulation(struct vcpu_vmx *vmx)
+{
+ int i;
+ u8 *bitmap = (u8 *)vmx->loaded_vmcs->msr_bitmap;
+
+ for (i = 0; i < ARRAY_SIZE(emulated_ro_guest_msrs); i++)
+ enable_msr_interception(bitmap, emulated_ro_guest_msrs[i], INTERCEPT_READ);
+}
diff --git a/arch/x86/kvm/vmx/pkvm/hyp/vmsr.h b/arch/x86/kvm/vmx/pkvm/hyp/vmsr.h
new file mode 100644
index 000000000000..1f39a37996f4
--- /dev/null
+++ b/arch/x86/kvm/vmx/pkvm/hyp/vmsr.h
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 Intel Corporation
+ */
+#ifndef _PKVM_VMSR_H_
+#define _PKVM_VMSR_H_
+
+int handle_read_msr(struct kvm_vcpu *vcpu);
+int handle_write_msr(struct kvm_vcpu *vcpu);
+
+#endif
diff --git a/arch/x86/kvm/vmx/pkvm/include/pkvm.h b/arch/x86/kvm/vmx/pkvm/include/pkvm.h
index 9b45627853b3..59bbe645baaa 100644
--- a/arch/x86/kvm/vmx/pkvm/include/pkvm.h
+++ b/arch/x86/kvm/vmx/pkvm/include/pkvm.h
@@ -106,6 +106,8 @@ PKVM_DECLARE(void *, pkvm_early_alloc_contig(unsigned int nr_pages));
PKVM_DECLARE(void *, pkvm_early_alloc_page(void));
PKVM_DECLARE(void, pkvm_early_alloc_init(void *virt, unsigned long size));
+PKVM_DECLARE(void, init_msr_emulation(struct vcpu_vmx *vmx));
+
PKVM_DECLARE(void, noop_handler(void));
PKVM_DECLARE(void, nmi_handler(void));
diff --git a/arch/x86/kvm/vmx/pkvm/pkvm_host.c b/arch/x86/kvm/vmx/pkvm/pkvm_host.c
index cbba3033ba63..90d7cddde9ef 100644
--- a/arch/x86/kvm/vmx/pkvm/pkvm_host.c
+++ b/arch/x86/kvm/vmx/pkvm/pkvm_host.c
@@ -280,6 +280,7 @@ static __init void init_execution_control(struct vcpu_vmx *vmx,
/* guest handles exception directly */
vmcs_write32(EXCEPTION_BITMAP, 0);
+ pkvm_sym(init_msr_emulation(vmx));
vmcs_write64(MSR_BITMAP, __pa(vmx->vmcs01.msr_bitmap));
/*
--
2.25.1
