[PATCH 2/4] KVM: SVM: Create a separate mapping for the SEV-ES save area

[Brijesh Singh <brijesh.singh@amd.com>]

From: Tom Lendacky <thomas.lendacky@amd.com>

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 <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/include/asm/svm.h | 87 +++++++++++++++++++++++++++++---------
 arch/x86/kvm/svm/sev.c     | 24 +++++------
 arch/x86/kvm/svm/svm.h     |  2 +-
 3 files changed, 80 insertions(+), 33 deletions(-)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 7c9cf4f3c164..3ce2e575a2de 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -227,6 +227,7 @@ 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;
@@ -243,8 +244,58 @@ 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;
@@ -272,22 +323,14 @@ 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;
@@ -299,23 +342,25 @@ 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;
 
+#define GHCB_SHARED_BUF_SIZE	2032
+
 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];
+	u8 shared_buffer[GHCB_SHARED_BUF_SIZE];
 
 	u8 reserved_1[10];
 	u16 protocol_version;	/* negotiated SEV-ES/GHCB protocol version */
@@ -323,13 +368,15 @@ 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		1024
 #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);
 }
@@ -399,7 +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 322553322202..c79da6af40b6 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -558,12 +558,20 @@ 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->sev_es.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];
@@ -591,14 +599,6 @@ static int sev_es_sync_vmsa(struct vcpu_svm *svm)
 	save->xss  = svm->vcpu.arch.ia32_xss;
 	save->dr6  = svm->vcpu.arch.dr6;
 
-	/*
-	 * 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->sev_es.vmsa, save, sizeof(*save));
-
 	return 0;
 }
 
@@ -2905,7 +2905,7 @@ void sev_es_vcpu_reset(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,
@@ -2915,7 +2915,7 @@ 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 daa8ca84afcc..d383d477bb29 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -168,7 +168,7 @@ struct svm_nested_state {
 
 struct vcpu_sev_es_state {
 	/* 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;
-- 
2.25.1