[PATCH v6 08/10] x86/sev: Handle CLFLUSH MMIO events
From: <hidden>
Date: 2024-06-10 10:21:41
Also in:
kexec, kvm, linux-coco, lkml, stable
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Joerg Roedel <redacted> Handle CLFLUSH instruction to MMIO memory in the #VC handler. The instruction is ignored by the handler, as the Hypervisor is responsible for cache management of emulated MMIO memory. Signed-off-by: Joerg Roedel <redacted> Signed-off-by: Vasant Karasulli <redacted> --- arch/x86/include/asm/insn-eval.h | 1 + arch/x86/kernel/sev-shared.c | 3 +++ arch/x86/lib/insn-eval-shared.c | 7 +++++++ 3 files changed, 11 insertions(+)
diff --git a/arch/x86/include/asm/insn-eval.h b/arch/x86/include/asm/insn-eval.h
index 54368a43abf6..3bcea641913a 100644
--- a/arch/x86/include/asm/insn-eval.h
+++ b/arch/x86/include/asm/insn-eval.h@@ -40,6 +40,7 @@ enum insn_mmio_type { INSN_MMIO_READ_ZERO_EXTEND, INSN_MMIO_READ_SIGN_EXTEND, INSN_MMIO_MOVS, + INSN_MMIO_IGNORE, }; enum insn_mmio_type insn_decode_mmio(struct insn *insn, int *bytes);
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 1b25a6cacec7..2a963ad84f10 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c@@ -1171,6 +1171,9 @@ static enum es_result vc_handle_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt) if (mmio == INSN_MMIO_DECODE_FAILED) return ES_DECODE_FAILED; + if (mmio == INSN_MMIO_IGNORE) + return ES_OK; + if (mmio != INSN_MMIO_WRITE_IMM && mmio != INSN_MMIO_MOVS) { reg_data = insn_get_modrm_reg_ptr(insn, ctxt->regs); if (!reg_data)
diff --git a/arch/x86/lib/insn-eval-shared.c b/arch/x86/lib/insn-eval-shared.c
index 02acdc2921ff..27fd347d84ae 100644
--- a/arch/x86/lib/insn-eval-shared.c
+++ b/arch/x86/lib/insn-eval-shared.c@@ -906,6 +906,13 @@ enum insn_mmio_type insn_decode_mmio(struct insn *insn, int *bytes) *bytes = 2; type = INSN_MMIO_READ_SIGN_EXTEND; break; + case 0xae: /* CLFLUSH */ + /* + * Ignore CLFLUSHes - those go to emulated MMIO anyway and the + * hypervisor is responsible for cache management. + */ + type = INSN_MMIO_IGNORE; + break; } break; }
--
2.34.1