KVM: PPC: Book3S HV: Fix doorbell emulation by adding DPDES support

Doorbell emulation is broken for KVM on PowerVM guests as support for DPDES was not added in the initial patch series. Due to this, a KVM on PowerVM guest cannot be booted with the XICS interrupt controller as doorbells are to be setup in the initial probe path when using XICS (pSeries_smp_probe()). Add DPDES support in the host KVM code to fix doorbell emulation. Fixes: 6ccbbc3 ("KVM: PPC: Add helper library for Guest State Buffers") Cc: [email protected] # v6.7+ Signed-off-by: Gautam Menghani <[email protected]> Signed-off-by: Michael Ellerman <[email protected]> Link: https://lore.kernel.org/stable/20240522082838.121769-1-gautam%40linux.ibm.com
linuxppc · May 24, 2024 · c8ed83b · c8ed83b
1 parent ec92a34
commit c8ed83b
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Showing 6 changed files with 27 additions and 4 deletions.
diff --git a/Documentation/arch/powerpc/kvm-nested.rst b/Documentation/arch/powerpc/kvm-nested.rst
@@ -546,7 +546,9 @@ table information.
 +--------+-------+----+--------+----------------------------------+
 | 0x1052 | 0x08  | RW |   T    | CTRL                             |
 +--------+-------+----+--------+----------------------------------+
-| 0x1053-|       |    |        | Reserved                         |
+| 0x1053 | 0x08  | RW |   T    | DPDES                            |
++--------+-------+----+--------+----------------------------------+
+| 0x1054-|       |    |        | Reserved                         |
 | 0x1FFF |       |    |        |                                  |
 +--------+-------+----+--------+----------------------------------+
 | 0x2000 | 0x04  | RW |   T    | CR                               |

diff --git a/arch/powerpc/include/asm/guest-state-buffer.h b/arch/powerpc/include/asm/guest-state-buffer.h
@@ -81,6 +81,7 @@
 #define KVMPPC_GSID_HASHKEYR			0x1050
 #define KVMPPC_GSID_HASHPKEYR			0x1051
 #define KVMPPC_GSID_CTRL			0x1052
+#define KVMPPC_GSID_DPDES			0x1053
 
 #define KVMPPC_GSID_CR				0x2000
 #define KVMPPC_GSID_PIDR			0x2001
@@ -110,7 +111,7 @@
 #define KVMPPC_GSE_META_COUNT (KVMPPC_GSE_META_END - KVMPPC_GSE_META_START + 1)
 
 #define KVMPPC_GSE_DW_REGS_START KVMPPC_GSID_GPR(0)
-#define KVMPPC_GSE_DW_REGS_END KVMPPC_GSID_CTRL
+#define KVMPPC_GSE_DW_REGS_END KVMPPC_GSID_DPDES
 #define KVMPPC_GSE_DW_REGS_COUNT \
 	(KVMPPC_GSE_DW_REGS_END - KVMPPC_GSE_DW_REGS_START + 1)
 

diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
@@ -594,6 +594,7 @@ static inline u##size kvmppc_get_##reg(struct kvm_vcpu *vcpu)		\
 
 
 KVMPPC_BOOK3S_VCORE_ACCESSOR(vtb, 64, KVMPPC_GSID_VTB)
+KVMPPC_BOOK3S_VCORE_ACCESSOR(dpdes, 64, KVMPPC_GSID_DPDES)
 KVMPPC_BOOK3S_VCORE_ACCESSOR_GET(arch_compat, 32, KVMPPC_GSID_LOGICAL_PVR)
 KVMPPC_BOOK3S_VCORE_ACCESSOR_GET(lpcr, 64, KVMPPC_GSID_LPCR)
 KVMPPC_BOOK3S_VCORE_ACCESSOR_SET(tb_offset, 64, KVMPPC_GSID_TB_OFFSET)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
@@ -4116,6 +4116,11 @@ static int kvmhv_vcpu_entry_nestedv2(struct kvm_vcpu *vcpu, u64 time_limit,
 	int trap;
 	long rc;
 
+	if (vcpu->arch.doorbell_request) {
+		vcpu->arch.doorbell_request = 0;
+		kvmppc_set_dpdes(vcpu, 1);
+	}
+
 	io = &vcpu->arch.nestedv2_io;
 
 	msr = mfmsr();
@@ -4278,9 +4283,16 @@ static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit,
 	if (kvmhv_on_pseries()) {
 		if (kvmhv_is_nestedv1())
 			trap = kvmhv_vcpu_entry_p9_nested(vcpu, time_limit, lpcr, tb);
-		else
+		else {
 			trap = kvmhv_vcpu_entry_nestedv2(vcpu, time_limit, lpcr, tb);
 
+			/* Remember doorbell if it is pending  */
+			if (kvmppc_get_dpdes(vcpu)) {
+				vcpu->arch.doorbell_request = 1;
+				kvmppc_set_dpdes(vcpu, 0);
+			}
+		}
+
 		/* H_CEDE has to be handled now, not later */
 		if (trap == BOOK3S_INTERRUPT_SYSCALL && !nested &&
 		    kvmppc_get_gpr(vcpu, 3) == H_CEDE) {

diff --git a/arch/powerpc/kvm/book3s_hv_nestedv2.c b/arch/powerpc/kvm/book3s_hv_nestedv2.c
@@ -311,6 +311,10 @@ static int gs_msg_ops_vcpu_fill_info(struct kvmppc_gs_buff *gsb,
 			rc = kvmppc_gse_put_u64(gsb, iden,
 						vcpu->arch.vcore->vtb);
 			break;
+		case KVMPPC_GSID_DPDES:
+			rc = kvmppc_gse_put_u64(gsb, iden,
+						vcpu->arch.vcore->dpdes);
+			break;
 		case KVMPPC_GSID_LPCR:
 			rc = kvmppc_gse_put_u64(gsb, iden,
 						vcpu->arch.vcore->lpcr);
@@ -543,6 +547,9 @@ static int gs_msg_ops_vcpu_refresh_info(struct kvmppc_gs_msg *gsm,
 		case KVMPPC_GSID_VTB:
 			vcpu->arch.vcore->vtb = kvmppc_gse_get_u64(gse);
 			break;
+		case KVMPPC_GSID_DPDES:
+			vcpu->arch.vcore->dpdes = kvmppc_gse_get_u64(gse);
+			break;
 		case KVMPPC_GSID_LPCR:
 			vcpu->arch.vcore->lpcr = kvmppc_gse_get_u64(gse);
 			break;

diff --git a/arch/powerpc/kvm/test-guest-state-buffer.c b/arch/powerpc/kvm/test-guest-state-buffer.c
@@ -151,7 +151,7 @@ static void test_gs_bitmap(struct kunit *test)
 		i++;
 	}
 
-	for (u16 iden = KVMPPC_GSID_GPR(0); iden <= KVMPPC_GSID_CTRL; iden++) {
+	for (u16 iden = KVMPPC_GSID_GPR(0); iden <= KVMPPC_GSID_DPDES; iden++) {
 		kvmppc_gsbm_set(&gsbm, iden);
 		kvmppc_gsbm_set(&gsbm1, iden);
 		KUNIT_EXPECT_TRUE(test, kvmppc_gsbm_test(&gsbm, iden));