From e7f78db9fbb18900c724fd8ebfc46b6962203b98 Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Wed, 15 May 2019 19:04:24 +0200 Subject: [PATCH] spapr/xive: Sanity checks of OV5 during CAS If a machine is started with ic-mode=xive but the guest only knows about XICS, eg. an RHEL 7.6 guest, the kernel panics. This is expected but a bit unfortunate since the crash doesn't provide much information for the end user to guess what's happening. Detect that during CAS and exit QEMU with a proper error message instead, like it is already done for the MMU. Even if this is less likely to happen, the opposite case of a guest that only knows about XIVE would certainly fail all the same if the machine is started with ic-mode=xics. Also, the only valid values a guest can pass in byte 23 of OV5 during CAS are 0b00 (XIVE legacy mode) and 0b01 (XIVE exploitation mode). Any other value is a bug, at least with the current spec. Again, it does not seem right to let the guest go on without a precise idea of the interrupt mode it asked for. Handle these cases as well. Reported-by: Satheesh Rajendran Signed-off-by: Greg Kurz Message-Id: <155793986451.464434.12887933000007255549.stgit@bahia.lan> Signed-off-by: David Gibson --- hw/ppc/spapr_hcall.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c index 6c16d2b120..63a55614b8 100644 --- a/hw/ppc/spapr_hcall.c +++ b/hw/ppc/spapr_hcall.c @@ -1513,6 +1513,7 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu, bool guest_radix; Error *local_err = NULL; bool raw_mode_supported = false; + bool guest_xive; cas_pvr = cas_check_pvr(spapr, cpu, &addr, &raw_mode_supported, &local_err); if (local_err) { @@ -1545,10 +1546,17 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu, error_report("guest requested hash and radix MMU, which is invalid."); exit(EXIT_FAILURE); } + if (spapr_ovec_test(ov5_guest, OV5_XIVE_BOTH)) { + error_report("guest requested an invalid interrupt mode"); + exit(EXIT_FAILURE); + } + /* The radix/hash bit in byte 24 requires special handling: */ guest_radix = spapr_ovec_test(ov5_guest, OV5_MMU_RADIX_300); spapr_ovec_clear(ov5_guest, OV5_MMU_RADIX_300); + guest_xive = spapr_ovec_test(ov5_guest, OV5_XIVE_EXPLOIT); + /* * HPT resizing is a bit of a special case, because when enabled * we assume an HPT guest will support it until it says it @@ -1633,6 +1641,22 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu, } /* + * Ensure the guest asks for an interrupt mode we support; otherwise + * terminate the boot. + */ + if (guest_xive) { + if (spapr->irq->ov5 == SPAPR_OV5_XIVE_LEGACY) { + error_report("Guest requested unavailable interrupt mode (XIVE)"); + exit(EXIT_FAILURE); + } + } else { + if (spapr->irq->ov5 == SPAPR_OV5_XIVE_EXPLOIT) { + error_report("Guest requested unavailable interrupt mode (XICS)"); + exit(EXIT_FAILURE); + } + } + + /* * Generate a machine reset when we have an update of the * interrupt mode. Only required when the machine supports both * modes. -- 2.11.4.GIT