[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v2] hw/i386/intel_iommu: Simplify vtd_find_as_from_bus_num()
From: |
Peter Xu |
Subject: |
Re: [PATCH v2] hw/i386/intel_iommu: Simplify vtd_find_as_from_bus_num() logic |
Date: |
Wed, 26 Feb 2020 15:20:54 -0500 |
On Wed, Feb 26, 2020 at 09:10:30PM +0100, Philippe Mathieu-Daudé wrote:
> The vtd_find_as_from_bus_num() function was introduced (in commit
> dbaabb25f) in a code format that could return an incorrect pointer,
> which was later fixed by commit a2e1cd41ccf.
> We could have avoid this by writing the if() statement differently.
> Do it now, in case this function is re-used. The code is easier to
> review (harder to miss bugs).
>
> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> ---
> Since v2: Re-worded commit description, patch sent without -w.
>
> This patch is easier to review with 'git-diff -w' (--ignore-all-space):
>
> @@ -987,14 +987,17 @@ static bool vtd_slpte_nonzero_rsvd(uint64_t slpte,
> uint32_t level)
> static VTDBus *vtd_find_as_from_bus_num(IntelIOMMUState *s, uint8_t bus_num)
> {
> VTDBus *vtd_bus = s->vtd_as_by_bus_num[bus_num];
> - if (!vtd_bus) {
> + GHashTableIter iter;
> +
> + if (vtd_bus) {
> + return vtd_bus;
> + }
> +
> /*
> * Iterate over the registered buses to find the one which
> * currently hold this bus number, and update the bus_num
> * lookup table:
> */
> - GHashTableIter iter;
> -
> g_hash_table_iter_init(&iter, s->vtd_as_by_busptr);
> while (g_hash_table_iter_next(&iter, NULL, (void **)&vtd_bus)) {
> if (pci_bus_num(vtd_bus->bus) == bus_num) {
> @@ -1002,9 +1005,8 @@ static VTDBus *vtd_find_as_from_bus_num(IntelIOMMUState
> *s, uint8_t bus_num)
> return vtd_bus;
> }
> }
> - vtd_bus = NULL;
> - }
> - return vtd_bus;
> +
> + return NULL;
> }
(However we'll need to read below after all... :)
Reviewed-by: Peter Xu <address@hidden>
--
Peter Xu