[Part1,RFC,v4,17/36] KVM: SVM: Create a separate mapping for the SEV-ES save area

Commit Message

Brijesh Singh July 7, 2021, 6:14 p.m. UTC

From: Tom Lendacky <[e-mail]>

The save area for SEV-ES/SEV-SNP guests, as used by the hardware, is
different from the save area of a non SEV-ES/SEV-SNP guest.

This is the first step in defining the multiple save areas to keep them
separate and ensuring proper operation amongst the different types of
guests. Create an SEV-ES/SEV-SNP save area and adjust usage to the new
save area definition where needed.

Signed-off-by: Tom Lendacky <[e-mail]>
Signed-off-by: Brijesh Singh <[e-mail]>
---
 arch/x86/include/asm/svm.h | 83 +++++++++++++++++++++++++++++---------
 arch/x86/kvm/svm/sev.c     | 24 +++++------
 arch/x86/kvm/svm/svm.h     |  2 +-
 3 files changed, 77 insertions(+), 32 deletions(-)

Patch

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index ff614cdcf628..a7fa24ec8ddf 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -228,6 +228,7 @@  struct vmcb_seg {
 	u64 base;
 } __packed;
 
+/* Save area definition for legacy and SEV-MEM guests */
 struct vmcb_save_area {
 	struct vmcb_seg es;
 	struct vmcb_seg cs;
@@ -244,8 +245,58 @@  struct vmcb_save_area {
 	u8 cpl;
 	u8 reserved_2[4];
 	u64 efer;
+	u8 reserved_3[112];
+	u64 cr4;
+	u64 cr3;
+	u64 cr0;
+	u64 dr7;
+	u64 dr6;
+	u64 rflags;
+	u64 rip;
+	u8 reserved_4[88];
+	u64 rsp;
+	u64 s_cet;
+	u64 ssp;
+	u64 isst_addr;
+	u64 rax;
+	u64 star;
+	u64 lstar;
+	u64 cstar;
+	u64 sfmask;
+	u64 kernel_gs_base;
+	u64 sysenter_cs;
+	u64 sysenter_esp;
+	u64 sysenter_eip;
+	u64 cr2;
+	u8 reserved_5[32];
+	u64 g_pat;
+	u64 dbgctl;
+	u64 br_from;
+	u64 br_to;
+	u64 last_excp_from;
+	u64 last_excp_to;
+	u8 reserved_6[72];
+	u32 spec_ctrl;		/* Guest version of SPEC_CTRL at 0x2E0 */
+} __packed;
+
+/* Save area definition for SEV-ES and SEV-SNP guests */
+struct sev_es_save_area {
+	struct vmcb_seg es;
+	struct vmcb_seg cs;
+	struct vmcb_seg ss;
+	struct vmcb_seg ds;
+	struct vmcb_seg fs;
+	struct vmcb_seg gs;
+	struct vmcb_seg gdtr;
+	struct vmcb_seg ldtr;
+	struct vmcb_seg idtr;
+	struct vmcb_seg tr;
+	u8 reserved_1[43];
+	u8 cpl;
+	u8 reserved_2[4];
+	u64 efer;
 	u8 reserved_3[104];
-	u64 xss;		/* Valid for SEV-ES only */
+	u64 xss;
 	u64 cr4;
 	u64 cr3;
 	u64 cr0;
@@ -273,22 +324,14 @@  struct vmcb_save_area {
 	u64 br_to;
 	u64 last_excp_from;
 	u64 last_excp_to;
-
-	/*
-	 * The following part of the save area is valid only for
-	 * SEV-ES guests when referenced through the GHCB or for
-	 * saving to the host save area.
-	 */
-	u8 reserved_7[72];
-	u32 spec_ctrl;		/* Guest version of SPEC_CTRL at 0x2E0 */
-	u8 reserved_7b[4];
+	u8 reserved_7[80];
 	u32 pkru;
-	u8 reserved_7a[20];
-	u64 reserved_8;		/* rax already available at 0x01f8 */
+	u8 reserved_9[20];
+	u64 reserved_10;	/* rax already available at 0x01f8 */
 	u64 rcx;
 	u64 rdx;
 	u64 rbx;
-	u64 reserved_9;		/* rsp already available at 0x01d8 */
+	u64 reserved_11;	/* rsp already available at 0x01d8 */
 	u64 rbp;
 	u64 rsi;
 	u64 rdi;
@@ -300,21 +343,21 @@  struct vmcb_save_area {
 	u64 r13;
 	u64 r14;
 	u64 r15;
-	u8 reserved_10[16];
+	u8 reserved_12[16];
 	u64 sw_exit_code;
 	u64 sw_exit_info_1;
 	u64 sw_exit_info_2;
 	u64 sw_scratch;
 	u64 sev_features;
-	u8 reserved_11[48];
+	u8 reserved_13[48];
 	u64 xcr0;
 	u8 valid_bitmap[16];
 	u64 x87_state_gpa;
 } __packed;
 
 struct ghcb {
-	struct vmcb_save_area save;
-	u8 reserved_save[2048 - sizeof(struct vmcb_save_area)];
+	struct sev_es_save_area save;
+	u8 reserved_save[2048 - sizeof(struct sev_es_save_area)];
 
 	u8 shared_buffer[2032];
 
@@ -324,13 +367,15 @@  struct ghcb {
 } __packed;
 
 
-#define EXPECTED_VMCB_SAVE_AREA_SIZE		1032
+#define EXPECTED_VMCB_SAVE_AREA_SIZE		740
+#define EXPECTED_SEV_ES_SAVE_AREA_SIZE		1032
 #define EXPECTED_VMCB_CONTROL_AREA_SIZE		272
 #define EXPECTED_GHCB_SIZE			PAGE_SIZE
 
 static inline void __unused_size_checks(void)
 {
 	BUILD_BUG_ON(sizeof(struct vmcb_save_area)	!= EXPECTED_VMCB_SAVE_AREA_SIZE);
+	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);
 }
@@ -401,7 +446,7 @@  struct vmcb {
 /* GHCB Accessor functions */
 
 #define GHCB_BITMAP_IDX(field)							\
-	(offsetof(struct vmcb_save_area, field) / sizeof(u64))
+	(offsetof(struct sev_es_save_area, field) / sizeof(u64))
 
 #define DEFINE_GHCB_ACCESSORS(field)						\
 	static inline bool ghcb_##field##_is_valid(const struct ghcb *ghcb)	\
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 8d36f0c73071..751a4604a51d 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -552,12 +552,20 @@  static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 
 static int sev_es_sync_vmsa(struct vcpu_svm *svm)
 {
-	struct vmcb_save_area *save = &svm->vmcb->save;
+	struct sev_es_save_area *save = svm->vmsa;
 
 	/* Check some debug related fields before encrypting the VMSA */
-	if (svm->vcpu.guest_debug || (save->dr7 & ~DR7_FIXED_1))
+	if (svm->vcpu.guest_debug || (svm->vmcb->save.dr7 & ~DR7_FIXED_1))
 		return -EINVAL;
 
+	/*
+	 * SEV-ES will use a VMSA that is pointed to by the VMCB, not
+	 * the traditional VMSA that is part of the VMCB. Copy the
+	 * traditional VMSA as it has been built so far (in prep
+	 * for LAUNCH_UPDATE_VMSA) to be the initial SEV-ES state.
+	 */
+	memcpy(save, &svm->vmcb->save, sizeof(svm->vmcb->save));
+
 	/* Sync registgers */
 	save->rax = svm->vcpu.arch.regs[VCPU_REGS_RAX];
 	save->rbx = svm->vcpu.arch.regs[VCPU_REGS_RBX];
@@ -584,14 +592,6 @@  static int sev_es_sync_vmsa(struct vcpu_svm *svm)
 	save->pkru = svm->vcpu.arch.pkru;
 	save->xss  = svm->vcpu.arch.ia32_xss;
 
-	/*
-	 * SEV-ES will use a VMSA that is pointed to by the VMCB, not
-	 * the traditional VMSA that is part of the VMCB. Copy the
-	 * traditional VMSA as it has been built so far (in prep
-	 * for LAUNCH_UPDATE_VMSA) to be the initial SEV-ES state.
-	 */
-	memcpy(svm->vmsa, save, sizeof(*save));
-
 	return 0;
 }
 
@@ -2606,7 +2606,7 @@  void sev_es_create_vcpu(struct vcpu_svm *svm)
 void sev_es_prepare_guest_switch(struct vcpu_svm *svm, unsigned int cpu)
 {
 	struct svm_cpu_data *sd = per_cpu(svm_data, cpu);
-	struct vmcb_save_area *hostsa;
+	struct sev_es_save_area *hostsa;
 
 	/*
 	 * As an SEV-ES guest, hardware will restore the host state on VMEXIT,
@@ -2616,7 +2616,7 @@  void sev_es_prepare_guest_switch(struct vcpu_svm *svm, unsigned int cpu)
 	vmsave(__sme_page_pa(sd->save_area));
 
 	/* XCR0 is restored on VMEXIT, save the current host value */
-	hostsa = (struct vmcb_save_area *)(page_address(sd->save_area) + 0x400);
+	hostsa = (struct sev_es_save_area *)(page_address(sd->save_area) + 0x400);
 	hostsa->xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
 
 	/* PKRU is restored on VMEXIT, save the current host value */
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 2908c6ab5bb4..bb64b7f1b433 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -170,7 +170,7 @@  struct vcpu_svm {
 	} shadow_msr_intercept;
 
 	/* SEV-ES support */
-	struct vmcb_save_area *vmsa;
+	struct sev_es_save_area *vmsa;
 	struct ghcb *ghcb;
 	struct kvm_host_map ghcb_map;
 	bool received_first_sipi;