git: d7d1becad4b6 - main - bhyve nvme: Fix Controller init error cases

The branch main has been updated by chuck:

URL: https://cgit.FreeBSD.org/src/commit/?id=d7d1becad4b692b97dd1f32706947aae5118294b

commit d7d1becad4b692b97dd1f32706947aae5118294b
Author:     Chuck Tuffli <chuck@FreeBSD.org>
AuthorDate: 2022-08-14 14:47:34 +0000
Commit:     Chuck Tuffli <chuck@FreeBSD.org>
CommitDate: 2022-08-14 14:47:34 +0000

    bhyve nvme: Fix Controller init error cases
    
    Fuzzing of bhyve uncovered an assertion failure in the NVMe emulation.
    Investigation uncovered several corner cases the code did not handle.
    This change handles several Controller initialization errors, including
     - bad AQ sizes
     - bad AQ vm_map_gpa
     - doorbell writes prior to RDY
     - doorbell writes to uninitialized queue
     - CSTS.RDY if CFS set
    
    PR:             256317,256319,256320,256322
    Reported by:    Cheolwoo Myung <cwmyung@snu.ac.kr>
    Reviewed by:    jhb
    Differential Revision:  https://reviews.freebsd.org/D35453
---
 usr.sbin/bhyve/pci_nvme.c | 55 ++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 50 insertions(+), 5 deletions(-)

diff --git a/usr.sbin/bhyve/pci_nvme.c b/usr.sbin/bhyve/pci_nvme.c
index e10c8bd437e2..46a8104be9f6 100644
--- a/usr.sbin/bhyve/pci_nvme.c
+++ b/usr.sbin/bhyve/pci_nvme.c
@@ -398,6 +398,7 @@ static void pci_nvme_io_done(struct blockif_req *, int);
 	((sts) >> NVME_CSTS_REG_RDY_SHIFT & NVME_CSTS_REG_RDY_MASK)
 
 #define	NVME_CSTS_RDY	(1 << NVME_CSTS_REG_RDY_SHIFT)
+#define	NVME_CSTS_CFS	(1 << NVME_CSTS_REG_CFS_SHIFT)
 
 /* Completion Queue status word utils */
 #define	NVME_STATUS_P	(1 << NVME_STATUS_P_SHIFT)
@@ -1081,30 +1082,61 @@ pci_nvme_reset(struct pci_nvme_softc *sc)
 	pthread_mutex_unlock(&sc->mtx);
 }
 
-static void
+static int
 pci_nvme_init_controller(struct vmctx *ctx, struct pci_nvme_softc *sc)
 {
 	uint16_t acqs, asqs;
 
 	DPRINTF("%s", __func__);
 
-	asqs = (sc->regs.aqa & NVME_AQA_REG_ASQS_MASK) + 1;
+	/*
+	 * NVMe 2.0 states that "enabling a controller while this field is
+	 * cleared to 0h produces undefined results" for both ACQS and
+	 * ASQS. If zero, set CFS and do not become ready.
+	 */
+	asqs = ONE_BASED(sc->regs.aqa & NVME_AQA_REG_ASQS_MASK);
+	if (asqs < 2) {
+		EPRINTLN("%s: illegal ASQS value %#x (aqa=%#x)", __func__,
+		    asqs - 1, sc->regs.aqa);
+		sc->regs.csts |= NVME_CSTS_CFS;
+		return (-1);
+	}
 	sc->submit_queues[0].size = asqs;
 	sc->submit_queues[0].qbase = vm_map_gpa(ctx, sc->regs.asq,
 	            sizeof(struct nvme_command) * asqs);
+	if (sc->submit_queues[0].qbase == NULL) {
+		EPRINTLN("%s: ASQ vm_map_gpa(%lx) failed", __func__,
+		    sc->regs.asq);
+		sc->regs.csts |= NVME_CSTS_CFS;
+		return (-1);
+	}
 
 	DPRINTF("%s mapping Admin-SQ guest 0x%lx, host: %p",
 	        __func__, sc->regs.asq, sc->submit_queues[0].qbase);
 
-	acqs = ((sc->regs.aqa >> NVME_AQA_REG_ACQS_SHIFT) &
-	    NVME_AQA_REG_ACQS_MASK) + 1;
+	acqs = ONE_BASED((sc->regs.aqa >> NVME_AQA_REG_ACQS_SHIFT) &
+	    NVME_AQA_REG_ACQS_MASK);
+	if (acqs < 2) {
+		EPRINTLN("%s: illegal ACQS value %#x (aqa=%#x)", __func__,
+		    acqs - 1, sc->regs.aqa);
+		sc->regs.csts |= NVME_CSTS_CFS;
+		return (-1);
+	}
 	sc->compl_queues[0].size = acqs;
 	sc->compl_queues[0].qbase = vm_map_gpa(ctx, sc->regs.acq,
 	         sizeof(struct nvme_completion) * acqs);
+	if (sc->compl_queues[0].qbase == NULL) {
+		EPRINTLN("%s: ACQ vm_map_gpa(%lx) failed", __func__,
+		    sc->regs.acq);
+		sc->regs.csts |= NVME_CSTS_CFS;
+		return (-1);
+	}
 	sc->compl_queues[0].intr_en = NVME_CQ_INTEN;
 
 	DPRINTF("%s mapping Admin-CQ guest 0x%lx, host: %p",
 	        __func__, sc->regs.acq, sc->compl_queues[0].qbase);
+
+	return (0);
 }
 
 static int
@@ -2872,6 +2904,12 @@ pci_nvme_write_bar_0(struct vmctx *ctx, struct pci_nvme_softc* sc,
 		uint64_t idx = belloffset / 8; /* door bell size = 2*int */
 		int is_sq = (belloffset % 8) < 4;
 
+		if ((sc->regs.csts & NVME_CSTS_RDY) == 0) {
+			WPRINTF("doorbell write prior to RDY (offset=%#lx)\n",
+			    offset);
+			return;
+		}
+
 		if (belloffset > ((sc->max_queues+1) * 8 - 4)) {
 			WPRINTF("guest attempted an overflow write offset "
 			         "0x%lx, val 0x%lx in %s",
@@ -2879,6 +2917,12 @@ pci_nvme_write_bar_0(struct vmctx *ctx, struct pci_nvme_softc* sc,
 			return;
 		}
 
+		if (is_sq) {
+			if (sc->submit_queues[idx].qbase == NULL)
+				return;
+		} else if (sc->compl_queues[idx].qbase == NULL)
+			return;
+
 		pci_nvme_handle_doorbell(ctx, sc, idx, is_sq, value);
 		return;
 	}
@@ -2945,7 +2989,8 @@ pci_nvme_write_bar_0(struct vmctx *ctx, struct pci_nvme_softc* sc,
 			sc->regs.cc &= ~NVME_CC_NEN_WRITE_MASK;
 			sc->regs.cc |= ccreg & NVME_CC_NEN_WRITE_MASK;
 			sc->regs.csts &= ~NVME_CSTS_RDY;
-		} else if (sc->pending_ios == 0) {
+		} else if ((sc->pending_ios == 0) &&
+		    !(sc->regs.csts & NVME_CSTS_CFS)) {
 			sc->regs.csts |= NVME_CSTS_RDY;
 		}
 		break;