On 18/02/2020 5:43 pm, James Morse wrote:
Hi Marc,
$subject typo: ~/DBGBIDR/DBGDIDR/
On 16/02/2020 18:53, Marc Zyngier wrote:
The AArch32 CP14 DBGDIDR has bit 15 set to RES1, which our current
emulation doesn't set. Just add the missing bit.
So it does.
Reviewed-by: James Morse <james.morse@xxxxxxx>
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 3e909b117f0c..da82c4b03aab 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1658,7 +1658,7 @@ static bool trap_dbgidr(struct kvm_vcpu *vcpu,
p->regval = ((((dfr >> ID_AA64DFR0_WRPS_SHIFT) & 0xf) << 28) |
(((dfr >> ID_AA64DFR0_BRPS_SHIFT) & 0xf) << 24) |
(((dfr >> ID_AA64DFR0_CTX_CMPS_SHIFT) & 0xf) << 20)
- | (6 << 16) | (el3 << 14) | (el3 << 12));
+ | (6 << 16) | (1 << 15) | (el3 << 14) | (el3 << 12));
Hmmm, where el3 is:
| u32 el3 = !!cpuid_feature_extract_unsigned_field(pfr, ID_AA64PFR0_EL3_SHIFT);
Aren't we depending on the compilers 'true' being 1 here?
Pretty much, but thankfully the only compilers we support are C compilers:
"The result of the logical negation operator ! is 0 if the value of its
operand compares unequal to 0, 1 if the value of its operand compares
equal to 0. The result has type int."
And now I have you to thank for flashbacks to bitwise logical operators
in Visual Basic... :P
Robin.
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