From cb7cef8b32033f6284a47d797edd5c19c5491698 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 15 Jul 2019 14:17:04 +0100 Subject: [PATCH] target/arm: Set VFP-related MVFR0 fields for arm926 and arm1026 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The ARMv5 architecture didn't specify detailed per-feature ID registers. Now that we're using the MVFR0 register fields to gate the existence of VFP instructions, we need to set up the correct values in the cpu->isar structure so that we still provide an FPU to the guest. This fixes a regression in the arm926 and arm1026 CPUs, which are the only ones that both have VFP and are ARMv5 or earlier. This regression was introduced by the VFP refactoring, and more specifically by commits 1120827fa182f0e76 and 266bd25c485597c, which accidentally disabled VFP short-vector support and double-precision support on these CPUs. Fixes: 1120827fa182f0e Fixes: 266bd25c485597c Fixes: https://bugs.launchpad.net/qemu/+bug/1836192 Reported-by: Christophe Lyon Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Reviewed-by: Alex Bennée Tested-by: Christophe Lyon Message-id: 20190711131241.22231-1-peter.maydell@linaro.org --- target/arm/cpu.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/target/arm/cpu.c b/target/arm/cpu.c index ad164a773b..1959467fdc 100644 --- a/target/arm/cpu.c +++ b/target/arm/cpu.c @@ -1666,6 +1666,12 @@ static void arm926_initfn(Object *obj) * set the field to indicate Jazelle support within QEMU. */ cpu->isar.id_isar1 = FIELD_DP32(cpu->isar.id_isar1, ID_ISAR1, JAZELLE, 1); + /* + * Similarly, we need to set MVFR0 fields to enable double precision + * and short vector support even though ARMv5 doesn't have this register. + */ + cpu->isar.mvfr0 = FIELD_DP32(cpu->isar.mvfr0, MVFR0, FPSHVEC, 1); + cpu->isar.mvfr0 = FIELD_DP32(cpu->isar.mvfr0, MVFR0, FPDP, 1); } static void arm946_initfn(Object *obj) @@ -1702,6 +1708,12 @@ static void arm1026_initfn(Object *obj) * set the field to indicate Jazelle support within QEMU. */ cpu->isar.id_isar1 = FIELD_DP32(cpu->isar.id_isar1, ID_ISAR1, JAZELLE, 1); + /* + * Similarly, we need to set MVFR0 fields to enable double precision + * and short vector support even though ARMv5 doesn't have this register. + */ + cpu->isar.mvfr0 = FIELD_DP32(cpu->isar.mvfr0, MVFR0, FPSHVEC, 1); + cpu->isar.mvfr0 = FIELD_DP32(cpu->isar.mvfr0, MVFR0, FPDP, 1); { /* The 1026 had an IFAR at c6,c0,0,1 rather than the ARMv6 c6,c0,0,2 */ -- 2.11.4.GIT