On Fri, Sep 18, 2026, Gokul K wrote: > guest_snprintf() is a varargs wrapper around guest_vsnprintf() that nothing > calls. Its declaration in test_util.h and its definition in > lib/guest_sprintf.c are the only two mentions anywhere under > tools/testing/selftests. > > The rest of the family is alive: guest_vsnprintf() does the work and > ucall_common.c calls it, so this deletes the wrapper and nothing else. > > No functional change intended. > > Signed-off-by: Gokul K <[email protected]> > --- > tools/testing/selftests/kvm/include/test_util.h | 1 - > tools/testing/selftests/kvm/lib/guest_sprintf.c | 12 ------------ > 2 files changed, 13 deletions(-) > > diff --git a/tools/testing/selftests/kvm/include/test_util.h > b/tools/testing/selftests/kvm/include/test_util.h > index a6a3e1657895..fbdf0e0c15d1 100644 > --- a/tools/testing/selftests/kvm/include/test_util.h > +++ b/tools/testing/selftests/kvm/include/test_util.h > @@ -238,7 +238,6 @@ static inline u32 atoi_non_negative(const char *name, > const char *num_str) > } > > int guest_vsnprintf(char *buf, int n, const char *fmt, va_list args); > -__printf(3, 4) int guest_snprintf(char *buf, int n, const char *fmt, ...); > > char *strdup_printf(const char *fmt, ...) __attribute__((format(printf, 1, > 2), nonnull(1))); > > diff --git a/tools/testing/selftests/kvm/lib/guest_sprintf.c > b/tools/testing/selftests/kvm/lib/guest_sprintf.c > index 7a33965349a7..6caebb456f3d 100644 > --- a/tools/testing/selftests/kvm/lib/guest_sprintf.c > +++ b/tools/testing/selftests/kvm/lib/guest_sprintf.c > @@ -300,15 +300,3 @@ int guest_vsnprintf(char *buf, int n, const char *fmt, > va_list args) > *str = '\0'; > return str - buf; > } > - > -int guest_snprintf(char *buf, int n, const char *fmt, ...) > -{ > - va_list va; > - int len; > - > - va_start(va, fmt); > - len = guest_vsnprintf(buf, n, fmt, va); > - va_end(va); > - > - return len; > -}
Hmm, I would rather turn guest_snprintf() into a macro so that it can be used in variadic functions. I can't think of any reason why this wouldn't work (and emperically, guest printing works as expected). --- From: Sean Christopherson <[email protected]> Date: Fri, 18 Sep 2026 08:57:37 -0700 Subject: [PATCH] KVM: selftests: Make guest_snprintf() a macro and use it as appropriate Turn guest_snprintf() into a macro so that it can be used by variadic functions, and use it in the ucall APIs instead of open coding the VA goo. Reported-by: Gokul K <[email protected]> Closes: https://lore.kernel.org/all/[email protected] Signed-off-by: Sean Christopherson <[email protected]> --- tools/testing/selftests/kvm/include/test_util.h | 12 +++++++++++- tools/testing/selftests/kvm/lib/guest_sprintf.c | 12 ------------ tools/testing/selftests/kvm/lib/ucall_common.c | 10 ++-------- 3 files changed, 13 insertions(+), 21 deletions(-) diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h index a6a3e1657895..817d4d5ca7cc 100644 --- a/tools/testing/selftests/kvm/include/test_util.h +++ b/tools/testing/selftests/kvm/include/test_util.h @@ -238,7 +238,17 @@ static inline u32 atoi_non_negative(const char *name, const char *num_str) } int guest_vsnprintf(char *buf, int n, const char *fmt, va_list args); -__printf(3, 4) int guest_snprintf(char *buf, int n, const char *fmt, ...); + +#define guest_snprintf(__buf, __n, __fmt) \ +({ \ + va_list va; \ + int len; \ + \ + va_start(va, __fmt); \ + len = guest_vsnprintf(__buf, __n, __fmt, va); \ + va_end(va); \ + len; \ +}) char *strdup_printf(const char *fmt, ...) __attribute__((format(printf, 1, 2), nonnull(1))); diff --git a/tools/testing/selftests/kvm/lib/guest_sprintf.c b/tools/testing/selftests/kvm/lib/guest_sprintf.c index 7a33965349a7..6caebb456f3d 100644 --- a/tools/testing/selftests/kvm/lib/guest_sprintf.c +++ b/tools/testing/selftests/kvm/lib/guest_sprintf.c @@ -300,15 +300,3 @@ int guest_vsnprintf(char *buf, int n, const char *fmt, va_list args) *str = '\0'; return str - buf; } - -int guest_snprintf(char *buf, int n, const char *fmt, ...) -{ - va_list va; - int len; - - va_start(va, fmt); - len = guest_vsnprintf(buf, n, fmt, va); - va_end(va); - - return len; -} diff --git a/tools/testing/selftests/kvm/lib/ucall_common.c b/tools/testing/selftests/kvm/lib/ucall_common.c index 029ce21f9f2f..e9df71197367 100644 --- a/tools/testing/selftests/kvm/lib/ucall_common.c +++ b/tools/testing/selftests/kvm/lib/ucall_common.c @@ -83,7 +83,6 @@ void ucall_assert(u64 cmd, const char *exp, const char *file, unsigned int line, const char *fmt, ...) { struct ucall *uc; - va_list va; uc = ucall_alloc(); uc->cmd = cmd; @@ -92,9 +91,7 @@ void ucall_assert(u64 cmd, const char *exp, const char *file, WRITE_ONCE(uc->args[GUEST_FILE], (u64)(file)); WRITE_ONCE(uc->args[GUEST_LINE], line); - va_start(va, fmt); - guest_vsnprintf(uc->buffer, UCALL_BUFFER_LEN, fmt, va); - va_end(va); + guest_snprintf(uc->buffer, UCALL_BUFFER_LEN, fmt); ucall_arch_do_ucall((gva_t)uc->hva); @@ -104,14 +101,11 @@ void ucall_assert(u64 cmd, const char *exp, const char *file, void ucall_fmt(u64 cmd, const char *fmt, ...) { struct ucall *uc; - va_list va; uc = ucall_alloc(); uc->cmd = cmd; - va_start(va, fmt); - guest_vsnprintf(uc->buffer, UCALL_BUFFER_LEN, fmt, va); - va_end(va); + guest_snprintf(uc->buffer, UCALL_BUFFER_LEN, fmt); ucall_arch_do_ucall((gva_t)uc->hva); base-commit: 70c944caf570fda2d79baa71435589a8db39f048 --
