On Fri, Dec 13, 2024 at 3:33 PM Hou Wenlong <houwenlong....@antgroup.com> wrote:
> On Fri, Dec 13, 2024 at 02:48:13PM +0800, lijiang wrote: > > On Wed, Dec 11, 2024 at 10:22 AM < > devel-requ...@lists.crash-utility.osci.io> > > wrote: > > > > > Date: Tue, 10 Dec 2024 20:18:43 +0800 > > > From: "Hou Wenlong" <houwenlong....@antgroup.com> > > > Subject: [Crash-utility] [PATCH] x86_64: Mark #VC stack unavailable > > > when CONFIG_AMD_MEM_ENCRYPT is not set > > > To: devel@lists.crash-utility.osci.io > > > Cc: Hou Wenlong <houwenlong....@antgroup.com> > > > Message-ID: <f1fca9918841de9a48f428d498f50964f1dab543.1733831073.git.h > > > ouwenlong....@antgroup.com> > > > > > > When 'CONFIG_AMD_MEM_ENCRYPT' is not set, the IDT handler for #VC is > not > > > registered, but the address of the #VC IST stack is still set in > > > tss_setup_ist(). Therefore, the name of the associated exception stack > > > is "UNKNOWN" instead of "VC". Although the base of the exception stack > > > is not zero and is available, it is not accessible, which will cause > the > > > backtrace to fail when attempting to access the #VC stack. To fix this, > > > remove the name check. > > > > > > > > Thank you for the fix, Hou. > > > > > > > Signe-off-by: Hou Wenlong <houwenlong....@antgroup.com> > > > --- > > > x86_64.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/x86_64.c b/x86_64.c > > > index e7f8fe25b31f..ee12ba095e6e 100644 > > > --- a/x86_64.c > > > +++ b/x86_64.c > > > @@ -1540,7 +1540,7 @@ x86_64_ist_init(void) > > > > > > ms->stkinfo.available[c][i] = TRUE; > > > /* VC stack can be unmapped if SEV-ES > is > > > disabled or not supported. */ > > > - if > (STREQ(ms->stkinfo.exception_stacks[i], > > > "VC") && > > > + if (ms->stkinfo.ebase[c][i] && > > > > > Can you help double check if the above condition is redundant in your > case? > > Seems the check '!accessible(ms->stkinfo.ebase[c][i])' should be enough. > > > Hi Lianbo, > > Yes, checking '!accessible(ms->stkinfo.ebase[c][i])' is sufficient. I > added the extra check because I noticed that a value of 0 seems to be > invalid for 'ms->stkinfo.ebase[c][i]', and there is a separate check for > 'ms->stkinfo.ebase[c][i] != 0' before it is used in other places. If we > remove the check, it could potentially be rewritten as: > > diff --git a/x86_64.c b/x86_64.c > index e7f8fe25b31f..c254c6ec7576 100644 > --- a/x86_64.c > +++ b/x86_64.c > @@ -1538,11 +1538,8 @@ x86_64_ist_init(void) > if (ms->stkinfo.ebase[c][i]) > ms->stkinfo.ebase[c][i] -= > ms->stkinfo.esize[i]; > > - ms->stkinfo.available[c][i] = TRUE; > /* VC stack can be unmapped if SEV-ES is > * disabled or not supported. */ > - if > (STREQ(ms->stkinfo.exception_stacks[i], > "VC") && > - !accessible(ms->stkinfo.ebase[c][i])) > - ms->stkinfo.available[c][i] = > FALSE; > + ms->stkinfo.available[c][i] = > accessible(ms->stkinfo.ebase[c][i]); > } > } > > This looks good to me. Thanks, Hou. > Thanks! > > > Thanks > > Lianbo > > > > !accessible(ms->stkinfo.ebase[c][i])) > > > ms->stkinfo.available[c][i] = > > > FALSE; > > > } > > > > > > base-commit: f13853cef53f5c5463a51021edbc81977e2b1405 > > > -- > > > 2.31.1 > > > > >
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