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linux/arch/x86/include/asm/sev.h
Brijesh Singh c2106a231c x86/sev: Get the AP jump table address from secrets page 
The GHCB specification section 2.7 states that when SEV-SNP is enabled,
a guest should not rely on the hypervisor to provide the address of the
AP jump table. Instead, if a guest BIOS wants to provide an AP jump
table, it should record the address in the SNP secrets page so the guest
operating system can obtain it directly from there.

Fix this on the guest kernel side by having SNP guests use the AP jump
table address published in the secrets page rather than issuing a GHCB
request to get it.

  [ mroth:
    - Improve error handling when ioremap()/memremap() return NULL
    - Don't mix function calls with declarations
    - Add missing __init
    - Tweak commit message ]

Fixes: 0afb6b660a ("x86/sev: Use SEV-SNP AP creation to start secondary CPUs")
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220422135624.114172-3-michael.roth@amd.com
2022-04-27 13:31:38 +02:00

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* AMD Encrypted Register State Support
*
* Author: Joerg Roedel <jroedel@suse.de>
*/
#ifndef __ASM_ENCRYPTED_STATE_H
#define __ASM_ENCRYPTED_STATE_H
#include <linux/types.h>
#include <asm/insn.h>
#include <asm/sev-common.h>
#include <asm/bootparam.h>
#define GHCB_PROTOCOL_MIN 1ULL
#define GHCB_PROTOCOL_MAX 2ULL
#define GHCB_DEFAULT_USAGE 0ULL
#define VMGEXIT() { asm volatile("rep; vmmcall\n\r"); }
enum es_result {
ES_OK, /* All good */
ES_UNSUPPORTED, /* Requested operation not supported */
ES_VMM_ERROR, /* Unexpected state from the VMM */
ES_DECODE_FAILED, /* Instruction decoding failed */
ES_EXCEPTION, /* Instruction caused exception */
ES_RETRY, /* Retry instruction emulation */
};
struct es_fault_info {
unsigned long vector;
unsigned long error_code;
unsigned long cr2;
};
struct pt_regs;
/* ES instruction emulation context */
struct es_em_ctxt {
struct pt_regs *regs;
struct insn insn;
struct es_fault_info fi;
};
/*
* AMD SEV Confidential computing blob structure. The structure is
* defined in OVMF UEFI firmware header:
* https://github.com/tianocore/edk2/blob/master/OvmfPkg/Include/Guid/ConfidentialComputingSevSnpBlob.h
*/
#define CC_BLOB_SEV_HDR_MAGIC 0x45444d41
struct cc_blob_sev_info {
u32 magic;
u16 version;
u16 reserved;
u64 secrets_phys;
u32 secrets_len;
u32 rsvd1;
u64 cpuid_phys;
u32 cpuid_len;
u32 rsvd2;
} __packed;
void do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code);
static inline u64 lower_bits(u64 val, unsigned int bits)
{
u64 mask = (1ULL << bits) - 1;
return (val & mask);
}
struct real_mode_header;
enum stack_type;
struct ghcb;
/* Early IDT entry points for #VC handler */
extern void vc_no_ghcb(void);
extern void vc_boot_ghcb(void);
extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
/* Software defined (when rFlags.CF = 1) */
#define PVALIDATE_FAIL_NOUPDATE 255
/* RMP page size */
#define RMP_PG_SIZE_4K 0
#define RMPADJUST_VMSA_PAGE_BIT BIT(16)
/* SNP Guest message request */
struct snp_req_data {
unsigned long req_gpa;
unsigned long resp_gpa;
unsigned long data_gpa;
unsigned int data_npages;
};
struct sev_guest_platform_data {
u64 secrets_gpa;
};
/*
* The secrets page contains 96-bytes of reserved field that can be used by
* the guest OS. The guest OS uses the area to save the message sequence
* number for each VMPCK.
*
* See the GHCB spec section Secret page layout for the format for this area.
*/
struct secrets_os_area {
u32 msg_seqno_0;
u32 msg_seqno_1;
u32 msg_seqno_2;
u32 msg_seqno_3;
u64 ap_jump_table_pa;
u8 rsvd[40];
u8 guest_usage[32];
} __packed;
#define VMPCK_KEY_LEN 32
/* See the SNP spec version 0.9 for secrets page format */
struct snp_secrets_page_layout {
u32 version;
u32 imien : 1,
rsvd1 : 31;
u32 fms;
u32 rsvd2;
u8 gosvw[16];
u8 vmpck0[VMPCK_KEY_LEN];
u8 vmpck1[VMPCK_KEY_LEN];
u8 vmpck2[VMPCK_KEY_LEN];
u8 vmpck3[VMPCK_KEY_LEN];
struct secrets_os_area os_area;
u8 rsvd3[3840];
} __packed;
#ifdef CONFIG_AMD_MEM_ENCRYPT
extern struct static_key_false sev_es_enable_key;
extern void __sev_es_ist_enter(struct pt_regs *regs);
extern void __sev_es_ist_exit(void);
static __always_inline void sev_es_ist_enter(struct pt_regs *regs)
{
if (static_branch_unlikely(&sev_es_enable_key))
__sev_es_ist_enter(regs);
}
static __always_inline void sev_es_ist_exit(void)
{
if (static_branch_unlikely(&sev_es_enable_key))
__sev_es_ist_exit();
}
extern int sev_es_setup_ap_jump_table(struct real_mode_header *rmh);
extern void __sev_es_nmi_complete(void);
static __always_inline void sev_es_nmi_complete(void)
{
if (static_branch_unlikely(&sev_es_enable_key))
__sev_es_nmi_complete();
}
extern int __init sev_es_efi_map_ghcbs(pgd_t *pgd);
extern enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb,
bool set_ghcb_msr,
struct es_em_ctxt *ctxt,
u64 exit_code, u64 exit_info_1,
u64 exit_info_2);
static inline int rmpadjust(unsigned long vaddr, bool rmp_psize, unsigned long attrs)
{
int rc;
/* "rmpadjust" mnemonic support in binutils 2.36 and newer */
asm volatile(".byte 0xF3,0x0F,0x01,0xFE\n\t"
: "=a"(rc)
: "a"(vaddr), "c"(rmp_psize), "d"(attrs)
: "memory", "cc");
return rc;
}
static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate)
{
bool no_rmpupdate;
int rc;
/* "pvalidate" mnemonic support in binutils 2.36 and newer */
asm volatile(".byte 0xF2, 0x0F, 0x01, 0xFF\n\t"
CC_SET(c)
: CC_OUT(c) (no_rmpupdate), "=a"(rc)
: "a"(vaddr), "c"(rmp_psize), "d"(validate)
: "memory", "cc");
if (no_rmpupdate)
return PVALIDATE_FAIL_NOUPDATE;
return rc;
}
void setup_ghcb(void);
void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr,
unsigned int npages);
void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr,
unsigned int npages);
void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op);
void snp_set_memory_shared(unsigned long vaddr, unsigned int npages);
void snp_set_memory_private(unsigned long vaddr, unsigned int npages);
void snp_set_wakeup_secondary_cpu(void);
bool snp_init(struct boot_params *bp);
void snp_abort(void);
int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err);
#else
static inline void sev_es_ist_enter(struct pt_regs *regs) { }
static inline void sev_es_ist_exit(void) { }
static inline int sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { return 0; }
static inline void sev_es_nmi_complete(void) { }
static inline int sev_es_efi_map_ghcbs(pgd_t *pgd) { return 0; }
static inline int pvalidate(unsigned long vaddr, bool rmp_psize, bool validate) { return 0; }
static inline int rmpadjust(unsigned long vaddr, bool rmp_psize, unsigned long attrs) { return 0; }
static inline void setup_ghcb(void) { }
static inline void __init
early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr, unsigned int npages) { }
static inline void __init
early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, unsigned int npages) { }
static inline void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op) { }
static inline void snp_set_memory_shared(unsigned long vaddr, unsigned int npages) { }
static inline void snp_set_memory_private(unsigned long vaddr, unsigned int npages) { }
static inline void snp_set_wakeup_secondary_cpu(void) { }
static inline bool snp_init(struct boot_params *bp) { return false; }
static inline void snp_abort(void) { }
static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input,
unsigned long *fw_err)
{
return -ENOTTY;
}
#endif
#endif
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