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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Dec 2022 20:06:21.8361 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 08bbcafc-89c7-4ff1-6afc-08dade0eabd4 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: CO1NAM11FT016.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR12MB4272 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Ashish Kalra Using kvm_write_guest() to sync the GHCB scratch buffer can fail due to host mapping being 2M, but RMP being 4K. The page fault handling in do_user_addr_fault() fails to split the 2M page to handle RMP fault due to it being called here in a non-preemptible context. Instead use the already kernel mapped ghcb to sync the scratch buffer when the scratch buffer is contained within the GHCB. Signed-off-by: Ashish Kalra Signed-off-by: Michael Roth --- arch/x86/kvm/svm/sev.c | 29 +++++++++++++++++++++-------- arch/x86/kvm/svm/svm.h | 2 ++ 2 files changed, 23 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index b0f25ced7bcf..4de952d1d446 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -3036,6 +3036,24 @@ static bool sev_es_sync_to_ghcb(struct vcpu_svm *svm) ghcb_set_sw_exit_info_1(ghcb, svm->sev_es.ghcb_sw_exit_info_1); ghcb_set_sw_exit_info_2(ghcb, svm->sev_es.ghcb_sw_exit_info_2); + /* Sync the scratch buffer area. */ + if (svm->sev_es.ghcb_sa_sync) { + if (svm->sev_es.ghcb_sa_contained) { + memcpy(ghcb->shared_buffer + svm->sev_es.ghcb_sa_offset, + svm->sev_es.ghcb_sa, svm->sev_es.ghcb_sa_len); + } else { + int ret; + + ret = kvm_write_guest(svm->vcpu.kvm, + svm->sev_es.ghcb_sa_gpa, + svm->sev_es.ghcb_sa, svm->sev_es.ghcb_sa_len); + if (ret) + pr_warn_ratelimited("unmap_ghcb: kvm_write_guest failed while syncing scratch area, gpa: %llx, ret: %d\n", + svm->sev_es.ghcb_sa_gpa, ret); + } + svm->sev_es.ghcb_sa_sync = false; + } + trace_kvm_vmgexit_exit(svm->vcpu.vcpu_id, ghcb); svm_unmap_ghcb(svm, &map); @@ -3248,14 +3266,6 @@ void sev_es_unmap_ghcb(struct vcpu_svm *svm) if (!svm->sev_es.ghcb_in_use) return; - /* Sync the scratch buffer area. */ - if (svm->sev_es.ghcb_sa_sync) { - kvm_write_guest(svm->vcpu.kvm, - svm->sev_es.ghcb_sa_gpa, - svm->sev_es.ghcb_sa, svm->sev_es.ghcb_sa_len); - svm->sev_es.ghcb_sa_sync = false; - } - sev_es_sync_to_ghcb(svm); svm->sev_es.ghcb_in_use = false; @@ -3321,6 +3331,8 @@ static int setup_vmgexit_scratch(struct vcpu_svm *svm, bool sync, u64 len) scratch_gpa_beg, scratch_gpa_end); goto e_scratch; } + svm->sev_es.ghcb_sa_contained = true; + svm->sev_es.ghcb_sa_offset = scratch_gpa_beg - ghcb_scratch_beg; } else { /* * The guest memory must be read into a kernel buffer, so @@ -3331,6 +3343,7 @@ static int setup_vmgexit_scratch(struct vcpu_svm *svm, bool sync, u64 len) len, GHCB_SCRATCH_AREA_LIMIT); goto e_scratch; } + svm->sev_es.ghcb_sa_contained = false; } if (svm->sev_es.ghcb_sa_alloc_len < len) { diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 4692ada13f02..38aa579f6f70 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -217,6 +217,8 @@ struct vcpu_sev_es_state { u64 ghcb_sa_gpa; u32 ghcb_sa_alloc_len; bool ghcb_sa_sync; + bool ghcb_sa_contained; + u32 ghcb_sa_offset; /* * SEV-ES support to hold the sw_exit_info return values to be