On Wed Jun 5, 2024 at 9:39 PM AEST, Gautam Menghani wrote:

Add support for using DPDES in the library for using guest state buffers. DPDES support is needed for enabling usage of doorbells in a L2 KVM on PAPR guest.

Reviewed-by: Nicholas Piggin npiggin@gmail.com

Fixes: 6ccbbc33f06a ("KVM: PPC: Add helper library for Guest State Buffers") Cc: stable@vger.kernel.org # v6.7 Signed-off-by: Gautam Menghani gautam@linux.ibm.com

---

Documentation/arch/powerpc/kvm-nested.rst | 4 +++- arch/powerpc/include/asm/guest-state-buffer.h | 3 ++- arch/powerpc/include/asm/kvm_book3s.h | 1 + arch/powerpc/kvm/book3s_hv_nestedv2.c | 7 +++++++ arch/powerpc/kvm/test-guest-state-buffer.c | 2 +- 5 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/Documentation/arch/powerpc/kvm-nested.rst b/Documentation/arch/powerpc/kvm-nested.rst index 630602a8aa00..5defd13cc6c1 100644 --- 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 index 808149f31576..d107abe1468f 100644 --- 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 index 3e1e2a698c9e..10618622d7ef 100644 --- 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_nestedv2.c b/arch/powerpc/kvm/book3s_hv_nestedv2.c index 8e6f5355f08b..36863fff2a99 100644 --- 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 index 4720b8dc8837..2571ccc618c9 100644 --- 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_GSE_DW_REGS_END; iden++) { kvmppc_gsbm_set(&gsbm, iden); kvmppc_gsbm_set(&gsbm1, iden); KUNIT_EXPECT_TRUE(test, kvmppc_gsbm_test(&gsbm, iden));

On Wed Jun 5, 2024 at 9:39 PM AEST, Gautam Menghani wrote:

Doorbell emulation is broken for KVM on PAPR guests as support for DPDES was not added in the initial patch series. Due to this, a KVM on PAPR guest with SMT > 1 cannot be booted with the XICS interrupt controller as doorbells are setup in the initial probe path when using XICS (pSeries_smp_probe()).

Command to replicate the above bug:

qemu-system-ppc64 \ -drive file=rhel.qcow2,format=qcow2 \ -m 20G \ -smp 8,cores=1,threads=8 \ -cpu host \ -nographic \ -machine pseries,ic-mode=xics -accel kvm

Add doorbell state handling support in the host KVM code to fix doorbell emulation.

Reviewed-by: Nicholas Piggin npiggin@gmail.com

Fixes: 19d31c5f1157 ("KVM: PPC: Add support for nestedv2 guests") Cc: stable@vger.kernel.org # v6.7 Signed-off-by: Gautam Menghani gautam@linux.ibm.com

---

arch/powerpc/kvm/book3s_hv.c | 5 +++++ 1 file changed, 5 insertions(+)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 35cb014a0c51..21c69647d27c 100644 --- 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();