On 6/2/21 12:58 PM, Bruno Piazera Larsen wrote:
For the use from ppc_cpu_get_phys_page_debug, you'd pass in
cpu_mmu_index(env, false).
ppc_cpu_get_phys_page_debug has 2 calls to ppc_xlate, one using the data MMU,
the other using the instruction MMU. I'm guessing I should pass both, right?
Yes.
But here we have another bit that confuses me: cpu_mmu_index returns 0 if in
user mode, or uses the information stored in env to get it, so I don't see how
that would be different from getting directly. Unless the point is to have
ppc_*_xlate be generic and pc_*_debug knows the info in env is correct. Is that it?
The issue is that
(1) ppc_*_xlate should perform the lookup requested, and mmu_idx
does not *necessarily* correspond to the current contents of
env->msr et al. See (2).
(2) There is a secondary call to ppc_radix64_partition_scoped_xlate
for which the second stage page table should be read
with hypervisor permissions, and not the permissions of the
original memory access.
Note that ppc_radix64_check_prot checks msr_pr directly.
Thus the second stage lookup should use mmu_idx = 5
(HV kernel virtual mode). If I understand things correctly...
+ const short HV = 1, IR = 2, DR = 3;
+ bool MSR[3];
+ MSR[HV] = dmmu_idx & 2,
+ MSR[IR] = immu_idx & 4,
+ MSR[DR] = dmmu_idx & 4;
There's no point in the array. Just use three different scalars (real_mode,
hv, and pr (note that pr is the major portion of the bug as reported)).
Additionally, you'll not be distinguishing immu_idx and dmmu_idx, but using
the single idx that's given.
Ah, yeah, that's the "more complex than necessary, but it was easy for me to
read" part. Scalars are a good solution. In this function in specific, PR
doesn't actually show up anywhere, so I would actually only need 2. Anyway,
will start working on this.
Oh, I'll note that your constants above are wrong. I think that you should
have some common routines in (mmu-)internal.h:
/*
* These correspond to the mmu_idx values computed in
* hreg_compute_hflags_value. See the tables therein.
*/
static inline bool mmuidx_pr(int idx) { return idx & 1; }
static inline bool mmuidx_real(int idx) { return idx & 2; }
static inline bool mmuidx_hv(int idx) { return idx & 4; }
because you'll want to use these past mmu-radix64.c.
Then you also have a single place to adjust if the mmu_idx are reordered at a
later date.
r~