Re: [PATCH v6 69/76] x86/realmode: Setup AP jump table
From: Borislav Petkov <bp@alien8.de>
Date: 2020-08-31 17:09:45
Also in:
kvm, lkml
On Mon, Aug 24, 2020 at 10:55:04AM +0200, Joerg Roedel wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h index 8f36ae021a7f..a19ce9681ec2 100644 --- a/arch/x86/include/uapi/asm/svm.h +++ b/arch/x86/include/uapi/asm/svm.h@@ -84,6 +84,9 @@ /* SEV-ES software-defined VMGEXIT events */ #define SVM_VMGEXIT_MMIO_READ 0x80000001 #define SVM_VMGEXIT_MMIO_WRITE 0x80000002 +#define SVM_VMGEXIT_AP_JUMP_TABLE 0x80000005 +#define SVM_VMGEXIT_SET_AP_JUMP_TABLE 0 +#define SVM_VMGEXIT_GET_AP_JUMP_TABLE 1
^^^^^^^^^^^^ One tab too many here.
quoted hunk ↗ jump to hunk
#define SVM_VMGEXIT_UNSUPPORTED_EVENT 0x8000ffff #define SVM_EXIT_ERR -1diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index 28fe95ecd508..09a45ccd6c1d 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c@@ -21,6 +21,8 @@ #include <linux/mm.h> #include <asm/cpu_entry_area.h> +#include <asm/stacktrace.h> +#include <asm/realmode.h> #include <asm/sev-es.h> #include <asm/insn-eval.h> #include <asm/fpu/internal.h>@@ -219,6 +221,9 @@ static __always_inline void sev_es_put_ghcb(struct ghcb_state *state) } } +/* Needed in vc_early_vc_forward_exception */
vc_early_forward_exception()
quoted hunk ↗ jump to hunk
+void do_early_exception(struct pt_regs *regs, int trapnr); + static inline u64 sev_es_rd_ghcb_msr(void) { return native_read_msr(MSR_AMD64_SEV_ES_GHCB);@@ -407,6 +412,69 @@ static bool vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt *ctxt, /* Include code shared with pre-decompression boot stage */ #include "sev-es-shared.c" +static u64 sev_es_get_jump_table_addr(void)
Static and used here only once - you can drop the previx "sev_es".
+{
+ struct ghcb_state state;
+ unsigned long flags;
+ struct ghcb *ghcb;
+ u64 ret;
+
+ local_irq_save(flags);
+
+ ghcb = sev_es_get_ghcb(&state);
+
+ vc_ghcb_invalidate(ghcb);
+ ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_JUMP_TABLE);
+ ghcb_set_sw_exit_info_1(ghcb, SVM_VMGEXIT_GET_AP_JUMP_TABLE);
+ ghcb_set_sw_exit_info_2(ghcb, 0);
+
+ sev_es_wr_ghcb_msr(__pa(ghcb));
+ VMGEXIT();
+
+ if (!ghcb_sw_exit_info_1_is_valid(ghcb) ||
+ !ghcb_sw_exit_info_2_is_valid(ghcb))
+ ret = 0;
+
+ ret = ghcb->save.sw_exit_info_2;
+
+ sev_es_put_ghcb(&state);
+
+ local_irq_restore(flags);
+
+ return ret;
+}
+
+int sev_es_setup_ap_jump_table(struct real_mode_header *rmh)
+{
+ u16 startup_cs, startup_ip;
+ phys_addr_t jump_table_pa;
+ u64 jump_table_addr;
+ u16 __iomem *jump_table;
+
+ jump_table_addr = sev_es_get_jump_table_addr();
+
+ /* Check if AP Jump Table is non-zero and page-aligned */
+ if (!jump_table_addr || jump_table_addr & ~PAGE_MASK)
+ return 0;
I think you need to return !0 here so that the panic() below fires with
a modified message:
panic("Failed to get/update SEV-ES AP Jump Table");
or are we gonna boot an UP guest still?
If not panic, at least a warning that at least some APs didn't come
up...
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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