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Message-ID: <20230111194001.1947849-3-dionnaglaze@google.com>
Date: Wed, 11 Jan 2023 19:39:56 +0000
From: Dionna Glaze <dionnaglaze@...gle.com>
To: linux-kernel@...r.kernel.org, x86@...nel.org
Cc: Dionna Glaze <dionnaglaze@...gle.com>,
Tom Lendacky <Thomas.Lendacky@....com>,
Paolo Bonzini <pbonzini@...hat.com>,
Joerg Roedel <jroedel@...e.de>,
Peter Gonda <pgonda@...gle.com>,
Thomas Gleixner <tglx@...utronix.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Ingo Molnar <mingo@...hat.com>,
Borislav Petkov <Borislav.Petkov@....com>,
"H. Peter Anvin" <hpa@...or.com>,
Venu Busireddy <venu.busireddy@...cle.com>,
Michael Roth <michael.roth@....com>,
"Kirill A. Shutemov" <kirill@...temov.name>,
Michael Sterritt <sterritt@...gle.com>
Subject: [PATCH v11 2/7] x86/sev: Change snp_guest_issue_request's fw_err
The GHCB specification declares that the firmware error value for a
guest request will be stored in the lower 32 bits of EXIT_INFO_2.
The upper 32 bits are for the VMM's own error code. The fw_err argument
is thus a misnomer, and callers will need access to all 64 bits.
The type of unsigned long also causes problems, since sw_exit_info2 is
u64 (unsigned long long) vs the argument's unsigned long*. A temporary
typedef is introduced for the err argument so it can be changed in a
later patch more cleanly.
The firmware might not even be called, so the call is bookended with
the no firmware call error and clearing the error.
Cc: Tom Lendacky <Thomas.Lendacky@....com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Joerg Roedel <jroedel@...e.de>
Cc: Peter Gonda <pgonda@...gle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <Borislav.Petkov@....com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Venu Busireddy <venu.busireddy@...cle.com>
Cc: Michael Roth <michael.roth@....com>
Cc: "Kirill A. Shutemov" <kirill@...temov.name>
Cc: Michael Sterritt <sterritt@...gle.com>
Fixes: d5af44dde546 ("x86/sev: Provide support for SNP guest request NAEs")
Reviewed-by: Tom Lendacky <Thomas.Lendacky@....com>
Reviewed-by: Borislav Petkov <Borislav.Petkov@....com>
Reviewed-by: Peter Gonda <pgonda@...gle.com>
Signed-off-by: Dionna Glaze <dionnaglaze@...gle.com>
---
arch/x86/include/asm/sev.h | 10 ++++++++--
arch/x86/kernel/sev.c | 10 ++++++----
2 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index ebc271bb6d8e..5b03ba18fee7 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -133,6 +133,12 @@ struct snp_secrets_page_layout {
u8 rsvd3[3840];
} __packed;
+/*
+ * Use a type alias temporarily to cleanly change the snp_issue_guest_request
+ * signature cleanly over multiple patches.
+ */
+typedef unsigned long sev_guestreq_err_t;
+
#ifdef CONFIG_AMD_MEM_ENCRYPT
extern struct static_key_false sev_es_enable_key;
extern void __sev_es_ist_enter(struct pt_regs *regs);
@@ -196,7 +202,7 @@ 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 __init __noreturn snp_abort(void);
-int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err);
+int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, sev_guestreq_err_t *exitinfo2);
#else
static inline void sev_es_ist_enter(struct pt_regs *regs) { }
static inline void sev_es_ist_exit(void) { }
@@ -217,7 +223,7 @@ 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)
+ sev_guestreq_err_t *exitinfo2)
{
return -ENOTTY;
}
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 679026a640ef..d1a6092b1e03 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -22,6 +22,7 @@
#include <linux/efi.h>
#include <linux/platform_device.h>
#include <linux/io.h>
+#include <linux/psp-sev.h>
#include <asm/cpu_entry_area.h>
#include <asm/stacktrace.h>
@@ -2175,7 +2176,7 @@ static int __init init_sev_config(char *str)
}
__setup("sev=", init_sev_config);
-int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err)
+int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, sev_guestreq_err_t *exitinfo2)
{
struct ghcb_state state;
struct es_em_ctxt ctxt;
@@ -2186,9 +2187,11 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned
if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
return -ENODEV;
- if (!fw_err)
+ if (!exitinfo2)
return -EINVAL;
+ *exitinfo2 = SEV_RET_NO_FW_CALL;
+
/*
* __sev_get_ghcb() needs to run with IRQs disabled because it is using
* a per-CPU GHCB.
@@ -2212,14 +2215,13 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned
if (ret)
goto e_put;
+ *exitinfo2 = ghcb->save.sw_exit_info_2;
if (ghcb->save.sw_exit_info_2) {
/* Number of expected pages are returned in RBX */
if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST &&
ghcb->save.sw_exit_info_2 == SNP_GUEST_REQ_INVALID_LEN)
input->data_npages = ghcb_get_rbx(ghcb);
- *fw_err = ghcb->save.sw_exit_info_2;
-
ret = -EIO;
}
--
2.39.0.314.g84b9a713c41-goog
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