KVM: SVM: Name and check reserved fields with structs offset

Rename reserved fields on all structs in arch/x86/include/asm/svm.h
following their offset within the structs. Include compile time checks for
this in the same place where other BUILD_BUG_ON for the structs are.

This also solves that fields of struct sev_es_save_area are named by their
order of appearance, but right now they jump from reserved_5 to reserved_7.

Link: https://lkml.org/lkml/2022/10/22/376
Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>
Message-Id: <20221024164448.203351-1-carlos.bilbao@amd.com>
[Use ASSERT_STRUCT_OFFSET + fix a couple wrong offsets. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 0361626..4352b46 100644 (file)
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -293,12 +293,13 @@ struct vmcb_save_area {
        struct vmcb_seg ldtr;
        struct vmcb_seg idtr;
        struct vmcb_seg tr;
-       u8 reserved_1[42];
+       /* Reserved fields are named following their struct offset */
+       u8 reserved_0xa0[42];
        u8 vmpl;
        u8 cpl;
-       u8 reserved_2[4];
+       u8 reserved_0xcc[4];
        u64 efer;
-       u8 reserved_3[112];
+       u8 reserved_0xd8[112];
        u64 cr4;
        u64 cr3;
        u64 cr0;
@@ -306,7 +307,7 @@ struct vmcb_save_area {
        u64 dr6;
        u64 rflags;
        u64 rip;
-       u8 reserved_4[88];
+       u8 reserved_0x180[88];
        u64 rsp;
        u64 s_cet;
        u64 ssp;
@@ -321,14 +322,14 @@ struct vmcb_save_area {
        u64 sysenter_esp;
        u64 sysenter_eip;
        u64 cr2;
-       u8 reserved_5[32];
+       u8 reserved_0x248[32];
        u64 g_pat;
        u64 dbgctl;
        u64 br_from;
        u64 br_to;
        u64 last_excp_from;
        u64 last_excp_to;
-       u8 reserved_6[72];
+       u8 reserved_0x298[72];
        u32 spec_ctrl;          /* Guest version of SPEC_CTRL at 0x2E0 */
 } __packed;
 
@@ -349,12 +350,12 @@ struct sev_es_save_area {
        u64 vmpl2_ssp;
        u64 vmpl3_ssp;
        u64 u_cet;
-       u8 reserved_1[2];
+       u8 reserved_0xc8[2];
        u8 vmpl;
        u8 cpl;
-       u8 reserved_2[4];
+       u8 reserved_0xcc[4];
        u64 efer;
-       u8 reserved_3[104];
+       u8 reserved_0xd8[104];
        u64 xss;
        u64 cr4;
        u64 cr3;
@@ -371,7 +372,7 @@ struct sev_es_save_area {
        u64 dr1_addr_mask;
        u64 dr2_addr_mask;
        u64 dr3_addr_mask;
-       u8 reserved_4[24];
+       u8 reserved_0x1c0[24];
        u64 rsp;
        u64 s_cet;
        u64 ssp;
@@ -386,21 +387,21 @@ struct sev_es_save_area {
        u64 sysenter_esp;
        u64 sysenter_eip;
        u64 cr2;
-       u8 reserved_5[32];
+       u8 reserved_0x248[32];
        u64 g_pat;
        u64 dbgctl;
        u64 br_from;
        u64 br_to;
        u64 last_excp_from;
        u64 last_excp_to;
-       u8 reserved_7[80];
+       u8 reserved_0x298[80];
        u32 pkru;
-       u8 reserved_8[20];
-       u64 reserved_9;         /* rax already available at 0x01f8 */
+       u32 tsc_aux;
+       u8 reserved_0x2f0[24];
        u64 rcx;
        u64 rdx;
        u64 rbx;
-       u64 reserved_10;        /* rsp already available at 0x01d8 */
+       u64 reserved_0x320;     /* rsp already available at 0x01d8 */
        u64 rbp;
        u64 rsi;
        u64 rdi;
@@ -412,7 +413,7 @@ struct sev_es_save_area {
        u64 r13;
        u64 r14;
        u64 r15;
-       u8 reserved_11[16];
+       u8 reserved_0x380[16];
        u64 guest_exit_info_1;
        u64 guest_exit_info_2;
        u64 guest_exit_int_info;
@@ -425,7 +426,7 @@ struct sev_es_save_area {
        u64 pcpu_id;
        u64 event_inj;
        u64 xcr0;
-       u8 reserved_12[16];
+       u8 reserved_0x3f0[16];
 
        /* Floating point area */
        u64 x87_dp;
@@ -443,23 +444,23 @@ struct sev_es_save_area {
 } __packed;
 
 struct ghcb_save_area {
-       u8 reserved_1[203];
+       u8 reserved_0x0[203];
        u8 cpl;
-       u8 reserved_2[116];
+       u8 reserved_0xcc[116];
        u64 xss;
-       u8 reserved_3[24];
+       u8 reserved_0x148[24];
        u64 dr7;
-       u8 reserved_4[16];
+       u8 reserved_0x168[16];
        u64 rip;
-       u8 reserved_5[88];
+       u8 reserved_0x180[88];
        u64 rsp;
-       u8 reserved_6[24];
+       u8 reserved_0x1e0[24];
        u64 rax;
-       u8 reserved_7[264];
+       u8 reserved_0x200[264];
        u64 rcx;
        u64 rdx;
        u64 rbx;
-       u8 reserved_8[8];
+       u8 reserved_0x320[8];
        u64 rbp;
        u64 rsi;
        u64 rdi;
@@ -471,12 +472,12 @@ struct ghcb_save_area {
        u64 r13;
        u64 r14;
        u64 r15;
-       u8 reserved_9[16];
+       u8 reserved_0x380[16];
        u64 sw_exit_code;
        u64 sw_exit_info_1;
        u64 sw_exit_info_2;
        u64 sw_scratch;
-       u8 reserved_10[56];
+       u8 reserved_0x3b0[56];
        u64 xcr0;
        u8 valid_bitmap[16];
        u64 x87_state_gpa;
@@ -490,7 +491,7 @@ struct ghcb {
 
        u8 shared_buffer[GHCB_SHARED_BUF_SIZE];
 
-       u8 reserved_1[10];
+       u8 reserved_0xff0[10];
        u16 protocol_version;   /* negotiated SEV-ES/GHCB protocol version */
        u32 ghcb_usage;
 } __packed;
@@ -502,6 +503,9 @@ struct ghcb {
 #define EXPECTED_VMCB_CONTROL_AREA_SIZE                1024
 #define EXPECTED_GHCB_SIZE                     PAGE_SIZE
 
+#define BUILD_BUG_RESERVED_OFFSET(x, y) \
+       ASSERT_STRUCT_OFFSET(struct x, reserved ## _ ## y, y)
+
 static inline void __unused_size_checks(void)
 {
        BUILD_BUG_ON(sizeof(struct vmcb_save_area)      != EXPECTED_VMCB_SAVE_AREA_SIZE);
@@ -509,6 +513,39 @@ static inline void __unused_size_checks(void)
        BUILD_BUG_ON(sizeof(struct sev_es_save_area)    != EXPECTED_SEV_ES_SAVE_AREA_SIZE);
        BUILD_BUG_ON(sizeof(struct vmcb_control_area)   != EXPECTED_VMCB_CONTROL_AREA_SIZE);
        BUILD_BUG_ON(sizeof(struct ghcb)                != EXPECTED_GHCB_SIZE);
+
+       /* Check offsets of reserved fields */
+
+       BUILD_BUG_RESERVED_OFFSET(vmcb_save_area, 0xa0);
+       BUILD_BUG_RESERVED_OFFSET(vmcb_save_area, 0xcc);
+       BUILD_BUG_RESERVED_OFFSET(vmcb_save_area, 0xd8);
+       BUILD_BUG_RESERVED_OFFSET(vmcb_save_area, 0x180);
+       BUILD_BUG_RESERVED_OFFSET(vmcb_save_area, 0x248);
+       BUILD_BUG_RESERVED_OFFSET(vmcb_save_area, 0x298);
+
+       BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0xc8);
+       BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0xcc);
+       BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0xd8);
+       BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x1c0);
+       BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x248);
+       BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x298);
+       BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x2f0);
+       BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x320);
+       BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x380);
+       BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x3f0);
+
+       BUILD_BUG_RESERVED_OFFSET(ghcb_save_area, 0x0);
+       BUILD_BUG_RESERVED_OFFSET(ghcb_save_area, 0xcc);
+       BUILD_BUG_RESERVED_OFFSET(ghcb_save_area, 0x148);
+       BUILD_BUG_RESERVED_OFFSET(ghcb_save_area, 0x168);
+       BUILD_BUG_RESERVED_OFFSET(ghcb_save_area, 0x180);
+       BUILD_BUG_RESERVED_OFFSET(ghcb_save_area, 0x1e0);
+       BUILD_BUG_RESERVED_OFFSET(ghcb_save_area, 0x200);
+       BUILD_BUG_RESERVED_OFFSET(ghcb_save_area, 0x320);
+       BUILD_BUG_RESERVED_OFFSET(ghcb_save_area, 0x380);
+       BUILD_BUG_RESERVED_OFFSET(ghcb_save_area, 0x3b0);
+
+       BUILD_BUG_RESERVED_OFFSET(ghcb, 0xff0);
 }
 
 struct vmcb {

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index efaaef2..69dbf17 100644 (file)
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2648,7 +2648,7 @@ static int setup_vmgexit_scratch(struct vcpu_svm *svm, bool sync, u64 len)
                ghcb_scratch_beg = control->ghcb_gpa +
                                   offsetof(struct ghcb, shared_buffer);
                ghcb_scratch_end = control->ghcb_gpa +
-                                  offsetof(struct ghcb, reserved_1);
+                                  offsetof(struct ghcb, reserved_0xff0);
 
                /*
                 * If the scratch area begins within the GHCB, it must be