[PATCH RESEND v4 16/23] KVM: x86: smm: add structs for KVM's smram layout
From: Maxim Levitsky
Date: Tue Oct 25 2022 - 08:52:35 EST
Add structs that will be used to define and read/write the KVM's
SMRAM layout, instead of reading/writing to raw offsets.
Also document the differences between KVM's SMRAM layout and SMRAM
layout that is used by real Intel/AMD cpus.
Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
---
arch/x86/kvm/smm.c | 94 +++++++++++++++++++++++++++++++++
arch/x86/kvm/smm.h | 127 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 221 insertions(+)
diff --git a/arch/x86/kvm/smm.c b/arch/x86/kvm/smm.c
index 1191a79cf027e5..01dab9fc3ab4b7 100644
--- a/arch/x86/kvm/smm.c
+++ b/arch/x86/kvm/smm.c
@@ -8,6 +8,97 @@
#include "cpuid.h"
#include "trace.h"
+#define CHECK_SMRAM32_OFFSET(field, offset) \
+ ASSERT_STRUCT_OFFSET(struct kvm_smram_state_32, field, offset - 0xFE00)
+
+#define CHECK_SMRAM64_OFFSET(field, offset) \
+ ASSERT_STRUCT_OFFSET(struct kvm_smram_state_64, field, offset - 0xFE00)
+
+static void check_smram_offsets(void)
+{
+ /* 32 bit SMRAM image */
+ CHECK_SMRAM32_OFFSET(reserved1, 0xFE00);
+ CHECK_SMRAM32_OFFSET(smbase, 0xFEF8);
+ CHECK_SMRAM32_OFFSET(smm_revision, 0xFEFC);
+ CHECK_SMRAM32_OFFSET(reserved2, 0xFF00);
+ CHECK_SMRAM32_OFFSET(cr4, 0xFF14);
+ CHECK_SMRAM32_OFFSET(reserved3, 0xFF18);
+ CHECK_SMRAM32_OFFSET(ds, 0xFF2C);
+ CHECK_SMRAM32_OFFSET(fs, 0xFF38);
+ CHECK_SMRAM32_OFFSET(gs, 0xFF44);
+ CHECK_SMRAM32_OFFSET(idtr, 0xFF50);
+ CHECK_SMRAM32_OFFSET(tr, 0xFF5C);
+ CHECK_SMRAM32_OFFSET(gdtr, 0xFF6C);
+ CHECK_SMRAM32_OFFSET(ldtr, 0xFF78);
+ CHECK_SMRAM32_OFFSET(es, 0xFF84);
+ CHECK_SMRAM32_OFFSET(cs, 0xFF90);
+ CHECK_SMRAM32_OFFSET(ss, 0xFF9C);
+ CHECK_SMRAM32_OFFSET(es_sel, 0xFFA8);
+ CHECK_SMRAM32_OFFSET(cs_sel, 0xFFAC);
+ CHECK_SMRAM32_OFFSET(ss_sel, 0xFFB0);
+ CHECK_SMRAM32_OFFSET(ds_sel, 0xFFB4);
+ CHECK_SMRAM32_OFFSET(fs_sel, 0xFFB8);
+ CHECK_SMRAM32_OFFSET(gs_sel, 0xFFBC);
+ CHECK_SMRAM32_OFFSET(ldtr_sel, 0xFFC0);
+ CHECK_SMRAM32_OFFSET(tr_sel, 0xFFC4);
+ CHECK_SMRAM32_OFFSET(dr7, 0xFFC8);
+ CHECK_SMRAM32_OFFSET(dr6, 0xFFCC);
+ CHECK_SMRAM32_OFFSET(gprs, 0xFFD0);
+ CHECK_SMRAM32_OFFSET(eip, 0xFFF0);
+ CHECK_SMRAM32_OFFSET(eflags, 0xFFF4);
+ CHECK_SMRAM32_OFFSET(cr3, 0xFFF8);
+ CHECK_SMRAM32_OFFSET(cr0, 0xFFFC);
+
+ /* 64 bit SMRAM image */
+ CHECK_SMRAM64_OFFSET(es, 0xFE00);
+ CHECK_SMRAM64_OFFSET(cs, 0xFE10);
+ CHECK_SMRAM64_OFFSET(ss, 0xFE20);
+ CHECK_SMRAM64_OFFSET(ds, 0xFE30);
+ CHECK_SMRAM64_OFFSET(fs, 0xFE40);
+ CHECK_SMRAM64_OFFSET(gs, 0xFE50);
+ CHECK_SMRAM64_OFFSET(gdtr, 0xFE60);
+ CHECK_SMRAM64_OFFSET(ldtr, 0xFE70);
+ CHECK_SMRAM64_OFFSET(idtr, 0xFE80);
+ CHECK_SMRAM64_OFFSET(tr, 0xFE90);
+ CHECK_SMRAM64_OFFSET(io_restart_rip, 0xFEA0);
+ CHECK_SMRAM64_OFFSET(io_restart_rcx, 0xFEA8);
+ CHECK_SMRAM64_OFFSET(io_restart_rsi, 0xFEB0);
+ CHECK_SMRAM64_OFFSET(io_restart_rdi, 0xFEB8);
+ CHECK_SMRAM64_OFFSET(io_restart_dword, 0xFEC0);
+ CHECK_SMRAM64_OFFSET(reserved1, 0xFEC4);
+ CHECK_SMRAM64_OFFSET(io_inst_restart, 0xFEC8);
+ CHECK_SMRAM64_OFFSET(auto_hlt_restart, 0xFEC9);
+ CHECK_SMRAM64_OFFSET(reserved2, 0xFECA);
+ CHECK_SMRAM64_OFFSET(efer, 0xFED0);
+ CHECK_SMRAM64_OFFSET(svm_guest_flag, 0xFED8);
+ CHECK_SMRAM64_OFFSET(svm_guest_vmcb_gpa, 0xFEE0);
+ CHECK_SMRAM64_OFFSET(svm_guest_virtual_int, 0xFEE8);
+ CHECK_SMRAM64_OFFSET(reserved3, 0xFEF0);
+ CHECK_SMRAM64_OFFSET(smm_revison, 0xFEFC);
+ CHECK_SMRAM64_OFFSET(smbase, 0xFF00);
+ CHECK_SMRAM64_OFFSET(reserved4, 0xFF04);
+ CHECK_SMRAM64_OFFSET(ssp, 0xFF18);
+ CHECK_SMRAM64_OFFSET(svm_guest_pat, 0xFF20);
+ CHECK_SMRAM64_OFFSET(svm_host_efer, 0xFF28);
+ CHECK_SMRAM64_OFFSET(svm_host_cr4, 0xFF30);
+ CHECK_SMRAM64_OFFSET(svm_host_cr3, 0xFF38);
+ CHECK_SMRAM64_OFFSET(svm_host_cr0, 0xFF40);
+ CHECK_SMRAM64_OFFSET(cr4, 0xFF48);
+ CHECK_SMRAM64_OFFSET(cr3, 0xFF50);
+ CHECK_SMRAM64_OFFSET(cr0, 0xFF58);
+ CHECK_SMRAM64_OFFSET(dr7, 0xFF60);
+ CHECK_SMRAM64_OFFSET(dr6, 0xFF68);
+ CHECK_SMRAM64_OFFSET(rflags, 0xFF70);
+ CHECK_SMRAM64_OFFSET(rip, 0xFF78);
+ CHECK_SMRAM64_OFFSET(gprs, 0xFF80);
+
+ BUILD_BUG_ON(sizeof(union kvm_smram) != 512);
+}
+
+#undef CHECK_SMRAM64_OFFSET
+#undef CHECK_SMRAM32_OFFSET
+
+
void kvm_smm_changed(struct kvm_vcpu *vcpu, bool entering_smm)
{
trace_kvm_smm_transition(vcpu->vcpu_id, vcpu->arch.smbase, entering_smm);
@@ -199,6 +290,8 @@ void enter_smm(struct kvm_vcpu *vcpu)
unsigned long cr0;
char buf[512];
+ check_smram_offsets();
+
memset(buf, 0, 512);
#ifdef CONFIG_X86_64
if (guest_cpuid_has(vcpu, X86_FEATURE_LM))
@@ -449,6 +542,7 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt,
u64 val, cr0, cr3, cr4;
int i, r;
+
for (i = 0; i < 16; i++)
*reg_write(ctxt, i) = GET_SMSTATE(u64, smstate, 0x7ff8 - i * 8);
diff --git a/arch/x86/kvm/smm.h b/arch/x86/kvm/smm.h
index a6795b93ba3002..bf5c7ffeb11efc 100644
--- a/arch/x86/kvm/smm.h
+++ b/arch/x86/kvm/smm.h
@@ -2,6 +2,8 @@
#ifndef ASM_KVM_SMM_H
#define ASM_KVM_SMM_H
+#include <linux/build_bug.h>
+
#define GET_SMSTATE(type, buf, offset) \
(*(type *)((buf) + (offset) - 0x7e00))
@@ -9,6 +11,131 @@
*(type *)((buf) + (offset) - 0x7e00) = val
#ifdef CONFIG_KVM_SMM
+
+
+/* 32 bit KVM's emulated SMM layout. Loosely based on Intel's layout */
+
+struct kvm_smm_seg_state_32 {
+ u32 flags;
+ u32 limit;
+ u32 base;
+} __packed;
+
+struct kvm_smram_state_32 {
+ u32 reserved1[62];
+ u32 smbase;
+ u32 smm_revision;
+ u32 reserved2[5];
+ u32 cr4; /* CR4 is not present in Intel/AMD SMRAM image */
+ u32 reserved3[5];
+
+ /*
+ * Segment state is not present/documented in the Intel/AMD SMRAM image
+ * Instead this area on Intel/AMD contains IO/HLT restart flags.
+ */
+ struct kvm_smm_seg_state_32 ds;
+ struct kvm_smm_seg_state_32 fs;
+ struct kvm_smm_seg_state_32 gs;
+ struct kvm_smm_seg_state_32 idtr; /* IDTR has only base and limit */
+ struct kvm_smm_seg_state_32 tr;
+ u32 reserved;
+ struct kvm_smm_seg_state_32 gdtr; /* GDTR has only base and limit */
+ struct kvm_smm_seg_state_32 ldtr;
+ struct kvm_smm_seg_state_32 es;
+ struct kvm_smm_seg_state_32 cs;
+ struct kvm_smm_seg_state_32 ss;
+
+ u32 es_sel;
+ u32 cs_sel;
+ u32 ss_sel;
+ u32 ds_sel;
+ u32 fs_sel;
+ u32 gs_sel;
+ u32 ldtr_sel;
+ u32 tr_sel;
+
+ u32 dr7;
+ u32 dr6;
+ u32 gprs[8]; /* GPRS in the "natural" X86 order (EAX/ECX/EDX.../EDI) */
+ u32 eip;
+ u32 eflags;
+ u32 cr3;
+ u32 cr0;
+} __packed;
+
+
+/* 64 bit KVM's emulated SMM layout. Based on AMD64 layout */
+
+struct kvm_smm_seg_state_64 {
+ u16 selector;
+ u16 attributes;
+ u32 limit;
+ u64 base;
+};
+
+struct kvm_smram_state_64 {
+
+ struct kvm_smm_seg_state_64 es;
+ struct kvm_smm_seg_state_64 cs;
+ struct kvm_smm_seg_state_64 ss;
+ struct kvm_smm_seg_state_64 ds;
+ struct kvm_smm_seg_state_64 fs;
+ struct kvm_smm_seg_state_64 gs;
+ struct kvm_smm_seg_state_64 gdtr; /* GDTR has only base and limit*/
+ struct kvm_smm_seg_state_64 ldtr;
+ struct kvm_smm_seg_state_64 idtr; /* IDTR has only base and limit*/
+ struct kvm_smm_seg_state_64 tr;
+
+ /* I/O restart and auto halt restart are not implemented by KVM */
+ u64 io_restart_rip;
+ u64 io_restart_rcx;
+ u64 io_restart_rsi;
+ u64 io_restart_rdi;
+ u32 io_restart_dword;
+ u32 reserved1;
+ u8 io_inst_restart;
+ u8 auto_hlt_restart;
+ u8 reserved2[6];
+
+ u64 efer;
+
+ /*
+ * Two fields below are implemented on AMD only, to store
+ * SVM guest vmcb address if the #SMI was received while in the guest mode.
+ */
+ u64 svm_guest_flag;
+ u64 svm_guest_vmcb_gpa;
+ u64 svm_guest_virtual_int; /* unknown purpose, not implemented */
+
+ u32 reserved3[3];
+ u32 smm_revison;
+ u32 smbase;
+ u32 reserved4[5];
+
+ /* ssp and svm_* fields below are not implemented by KVM */
+ u64 ssp;
+ u64 svm_guest_pat;
+ u64 svm_host_efer;
+ u64 svm_host_cr4;
+ u64 svm_host_cr3;
+ u64 svm_host_cr0;
+
+ u64 cr4;
+ u64 cr3;
+ u64 cr0;
+ u64 dr7;
+ u64 dr6;
+ u64 rflags;
+ u64 rip;
+ u64 gprs[16]; /* GPRS in a reversed "natural" X86 order (R15/R14/../RCX/RAX.) */
+};
+
+union kvm_smram {
+ struct kvm_smram_state_64 smram64;
+ struct kvm_smram_state_32 smram32;
+ u8 bytes[512];
+};
+
static inline int kvm_inject_smi(struct kvm_vcpu *vcpu)
{
kvm_make_request(KVM_REQ_SMI, vcpu);
--
2.34.3