Svpbmt extension is necessary for chaning the memory type for a page contains
a combination of attributes that indicate the cacheability, idempotency,
and ordering properties for access to that page.
As a part of the patch the following is introduced:
- Svpbmt memory type defintions: PTE_PBMT_{NOCACHE,IO}.
- PAGE_HYPERVISOR_{NOCACHE,WC}.
- RISCV_ISA_EXT_svpbmt and add a check in runtime that Svpbmt is
supported by platform.
- Update riscv/booting.txt with information about Svpbmt.
- Update logic of pt_update_entry() to take into account PBMT bits.
Use 'unsigned long' for pte_attr_t as PBMT bits are 61 and 62 and it doesn't
fit into 'unsigned int'. Also, update function prototypes which uses
'unsigned int' for flags/attibutes.
Enable Svpbmt for testing in QEMU as it is now mandatory for Xen work.
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
H provides additional instructions and CSRs that control the new stage of
address translation and support hosting a guest OS in virtual S-mode
(VS-mode).
According to the Unprivileged Architecture (version 20240411) specification:
```
Table 74 summarizes the standardized extension names. The table also defines
the canonical order in which extension names must appear in the name string,
with top-to-bottom in table indicating first-to-last in the name string, e.g.,
RV32IMACV is legal, whereas RV32IMAVC is not.
```
According to Table 74, the h extension is placed last in the one-letter
extensions name part of the ISA string.
`h` is a standalone extension based on the patch [1] but it wasn't so
before.
As the minimal supported GCC version to build Xen for RISC-V is 12.2.0,
and for that version, h is still considered a prefix for the hypervisor
extension but the name of hypervisor extension must be more then 1 letter
extension, a workaround ( with using `hh` as an H extension name ) is
implemented as otherwise the following compilation error will occur:
error: '-march=rv64gc_h_zbb_zihintpause': name of hypervisor extension
must be more than 1 letter
After GCC version 13.1.0, the commit [1] introducing H extension support
allows us to drop the workaround with `hh` as hypervisor extension name
and use only one h in -march.
[1] https://github.com/gcc-mirror/gcc/commit/0cd11d301013af50a3fae0694c909952e94e20d5#diff-d6f7db0db31bfb339b01bec450f1b905381eb4730cc5ab2b2794971e34647d64R148
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Currently, RISC-V requires two extensions: _zbb and _zihintpause.
This patch introduces a compiler check to check if these extensions
are supported.
Additionally, it introduces the riscv/booting.txt file, which contains
information about the extensions that should be supported by the platform.
In the future, a feature will be introduced to check whether an extension
is supported at runtime.
However, this feature requires functionality for parsing device tree
source (DTS), which is not yet available.
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Oleksii Kurochko